diff --git a/plugins/libcalendaring/libcalendaring.js b/plugins/libcalendaring/libcalendaring.js
index fea85fde..fcf1f4fb 100644
--- a/plugins/libcalendaring/libcalendaring.js
+++ b/plugins/libcalendaring/libcalendaring.js
@@ -1,1199 +1,1205 @@
 /**
  * Basic Javascript utilities for calendar-related plugins
  *
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * @licstart  The following is the entire license notice for the
  * JavaScript code in this page.
  *
  * Copyright (C) 2012-2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  * @licend  The above is the entire license notice
  * for the JavaScript code in this page.
  */
 
 function rcube_libcalendaring(settings)
 {
     // member vars
     this.settings = settings || {};
     this.alarm_ids = [];
     this.alarm_dialog = null;
     this.snooze_popup = null;
     this.dismiss_link = null;
     this.group2expand = {};
 
     // abort if env isn't set
     if (!settings || !settings.date_format)
       return;
 
     // private vars
     var me = this;
     var gmt_offset = (new Date().getTimezoneOffset() / -60) - (settings.timezone || 0) - (settings.dst || 0);
     var client_timezone = new Date().getTimezoneOffset();
 
     // general datepicker settings
     var datepicker_settings = {
         // translate from fullcalendar format to datepicker format
         dateFormat: settings.date_format.replace(/M/g, 'm').replace(/mmmmm/, 'MM').replace(/mmm/, 'M').replace(/dddd/, 'DD').replace(/ddd/, 'D').replace(/yy/g, 'y'),
         firstDay : settings.first_day,
         dayNamesMin: settings.days_short,
         monthNames: settings.months,
         monthNamesShort: settings.months,
         changeMonth: false,
         showOtherMonths: true,
         selectOtherMonths: true
     };
 
 
     /**
      * Quote html entities
      */
     var Q = this.quote_html = function(str)
     {
       return String(str).replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
     };
 
     /**
      * Create a nice human-readable string for the date/time range
      */
     this.event_date_text = function(event, voice)
     {
       if (!event.start)
         return '';
       if (!event.end)
         event.end = event.start;
 
       var fromto, duration = event.end.getTime() / 1000 - event.start.getTime() / 1000,
         until = voice ? ' ' + rcmail.gettext('until','libcalendaring') + ' ' : ' — ';
       if (event.allDay) {
         fromto = this.format_datetime(event.start, 1, voice)
           + (duration > 86400 || event.start.getDay() != event.end.getDay() ? until + this.format_datetime(event.end, 1, voice) : '');
       }
       else if (duration < 86400 && event.start.getDay() == event.end.getDay()) {
         fromto = this.format_datetime(event.start, 0, voice)
           + (duration > 0 ? until + this.format_datetime(event.end, 2, voice) : '');
       }
       else {
         fromto = this.format_datetime(event.start, 0, voice)
           + (duration > 0 ? until + this.format_datetime(event.end, 0, voice) : '');
       }
 
       return fromto;
     };
 
 
     /**
      * From time and date strings to a real date object
      */
     this.parse_datetime = function(time, date)
     {
         // we use the utility function from datepicker to parse dates
         var date = date ? $.datepicker.parseDate(datepicker_settings.dateFormat, date, datepicker_settings) : new Date();
 
         var time_arr = time.replace(/\s*[ap][.m]*/i, '').replace(/0([0-9])/g, '$1').split(/[:.]/);
         if (!isNaN(time_arr[0])) {
             date.setHours(time_arr[0]);
         if (time.match(/p[.m]*/i) && date.getHours() < 12)
             date.setHours(parseInt(time_arr[0]) + 12);
         else if (time.match(/a[.m]*/i) && date.getHours() == 12)
             date.setHours(0);
       }
       if (!isNaN(time_arr[1]))
             date.setMinutes(time_arr[1]);
 
       return date;
     }
 
     /**
      * Convert an ISO 8601 formatted date string from the server into a Date object.
      * Timezone information will be ignored, the server already provides dates in user's timezone.
      */
     this.parseISO8601 = function(s)
     {
         // force d to be on check's YMD, for daylight savings purposes
         var fixDate = function(d, check) {
             if (+d) { // prevent infinite looping on invalid dates
                 while (d.getDate() != check.getDate()) {
                     d.setTime(+d + (d < check ? 1 : -1) * 3600000);
                 }
             }
         }
 
         // derived from http://delete.me.uk/2005/03/iso8601.html
         var m = s && s.match(/^([0-9]{4})(-([0-9]{2})(-([0-9]{2})([T ]([0-9]{2}):([0-9]{2})(:([0-9]{2})(\.([0-9]+))?)?(Z|(([-+])([0-9]{2})(:?([0-9]{2}))?))?)?)?)?$/);
         if (!m) {
             return null;
         }
 
         var date = new Date(m[1], 0, 2),
             check = new Date(m[1], 0, 2, 9, 0);
         if (m[3]) {
             date.setMonth(m[3] - 1);
             check.setMonth(m[3] - 1);
         }
         if (m[5]) {
             date.setDate(m[5]);
             check.setDate(m[5]);
         }
         fixDate(date, check);
         if (m[7]) {
             date.setHours(m[7]);
         }
         if (m[8]) {
             date.setMinutes(m[8]);
         }
         if (m[10]) {
             date.setSeconds(m[10]);
         }
         if (m[12]) {
             date.setMilliseconds(Number("0." + m[12]) * 1000);
         }
         fixDate(date, check);
 
         return date;
     }
 
     /**
      * Turn the given date into an ISO 8601 date string understandable by PHPs strtotime()
      */
     this.date2ISO8601 = function(date)
     {
         var zeropad = function(num) { return (num < 10 ? '0' : '') + num; };
 
         return date.getFullYear() + '-' + zeropad(date.getMonth()+1) + '-' + zeropad(date.getDate())
             + 'T' + zeropad(date.getHours()) + ':' + zeropad(date.getMinutes()) + ':' + zeropad(date.getSeconds());
     };
 
     /**
      * Format the given date object according to user's prefs
      */
     this.format_datetime = function(date, mode, voice)
     {
         var res = '';
         if (!mode || mode == 1) {
           res += $.datepicker.formatDate(voice ? 'MM d yy' : datepicker_settings.dateFormat, date, datepicker_settings);
         }
         if (!mode) {
             res += voice ? ' ' + rcmail.gettext('at','libcalendaring') + ' ' : ' ';
         }
         if (!mode || mode == 2) {
             res += this.format_time(date, voice);
         }
 
         return res;
     }
 
     /**
      * Clone from fullcalendar.js
      */
     this.format_time = function(date, voice)
     {
         var zeroPad = function(n) { return (n < 10 ? '0' : '') + n; }
         var formatters = {
             s   : function(d) { return d.getSeconds() },
             ss  : function(d) { return zeroPad(d.getSeconds()) },
             m   : function(d) { return d.getMinutes() },
             mm  : function(d) { return zeroPad(d.getMinutes()) },
             h   : function(d) { return d.getHours() % 12 || 12 },
             hh  : function(d) { return zeroPad(d.getHours() % 12 || 12) },
             H   : function(d) { return d.getHours() },
             HH  : function(d) { return zeroPad(d.getHours()) },
             t   : function(d) { return d.getHours() < 12 ? 'a' : 'p' },
             tt  : function(d) { return d.getHours() < 12 ? 'am' : 'pm' },
             T   : function(d) { return d.getHours() < 12 ? 'A' : 'P' },
             TT  : function(d) { return d.getHours() < 12 ? 'AM' : 'PM' }
         };
 
         var i, i2, c, formatter, res = '',
           format = voice ? settings['time_format'].replace(':',' ').replace('HH','H').replace('hh','h').replace('mm','m').replace('ss','s') : settings['time_format'];
         for (i=0; i < format.length; i++) {
             c = format.charAt(i);
             for (i2=Math.min(i+2, format.length); i2 > i; i2--) {
                 if (formatter = formatters[format.substring(i, i2)]) {
                     res += formatter(date);
                     i = i2 - 1;
                     break;
                 }
             }
             if (i2 == i) {
                 res += c;
             }
         }
 
         return res;
     }
 
     /**
      * Convert the given Date object into a unix timestamp respecting browser's and user's timezone settings
      */
     this.date2unixtime = function(date)
     {
         var dst_offset = (client_timezone - date.getTimezoneOffset()) * 60;  // adjust DST offset
         return Math.round(date.getTime()/1000 + gmt_offset * 3600 + dst_offset);
     }
 
     /**
      * Turn a unix timestamp value into a Date object
      */
     this.fromunixtime = function(ts)
     {
         ts -= gmt_offset * 3600;
         var date = new Date(ts * 1000),
             dst_offset = (client_timezone - date.getTimezoneOffset()) * 60;
         if (dst_offset)  // adjust DST offset
             date.setTime((ts + 3600) * 1000);
         return date;
     }
 
     /**
      * Simple plaintext to HTML converter, makig URLs clickable
      */
     this.text2html = function(str, maxlen, maxlines)
     {
         var html = Q(String(str));
 
         // limit visible text length
         if (maxlen) {
             var morelink = '<span>... <a href="#more" onclick="$(this).parent().hide().next().show();return false" class="morelink">'+rcmail.gettext('showmore','libcalendaring')+'</a></span><span style="display:none">',
                 lines = html.split(/\r?\n/),
                 words, out = '', len = 0;
 
             for (var i=0; i < lines.length; i++) {
                 len += lines[i].length;
                 if (maxlines && i == maxlines - 1) {
                     out += lines[i] + '\n' + morelink;
                     maxlen = html.length * 2;
                 }
                 else if (len > maxlen) {
                     len = out.length;
                     words = lines[i].split(' ');
                     for (var j=0; j < words.length; j++) {
                         len += words[j].length + 1;
                         out += words[j] + ' ';
                         if (len > maxlen) {
                             out += morelink;
                             maxlen = html.length * 2;
                             maxlines = 0;
                         }
                     }
                     out += '\n';
                 }
                 else
                     out += lines[i] + '\n';
             }
 
             if (maxlen > str.length)
                 out += '</span>';
 
             html = out;
         }
 
         // simple link parser (similar to rcube_string_replacer class in PHP)
         var utf_domain = '[^?&@"\'/\\(\\)\\s\\r\\t\\n]+\\.([^\x00-\x2f\x3b-\x40\x5b-\x60\x7b-\x7f]{2,}|xn--[a-z0-9]{2,})';
         var url1 = '.:;,', url2 = 'a-z0-9%=#@+?&/_~\\[\\]-';
         var link_pattern = new RegExp('([hf]t+ps?://)('+utf_domain+'(['+url1+']?['+url2+']+)*)', 'ig');
         var mailto_pattern = new RegExp('([^\\s\\n\\(\\);]+@'+utf_domain+')', 'ig');
         var link_replace = function(matches, p1, p2) {
           var title = '', text = p2;
           if (p2 && p2.length > 55) {
             text = p2.substr(0, 45) + '...' + p2.substr(-8);
             title = p1 + p2;
           }
           return '<a href="'+p1+p2+'" class="extlink" target="_blank" title="'+title+'">'+p1+text+'</a>'
         };
 
         return html
             .replace(link_pattern, link_replace)
             .replace(mailto_pattern, '<a href="mailto:$1">$1</a>')
             .replace(/(mailto:)([^"]+)"/g, '$1$2" onclick="rcmail.command(\'compose\', \'$2\');return false"')
             .replace(/\n/g, "<br/>");
     };
 
     this.init_alarms_edit = function(prefix, index)
     {
         var edit_type = $(prefix+' select.edit-alarm-type'),
           dom_id = edit_type.attr('id');
 
         // register events on alarm fields
         edit_type.change(function(){
             $(this).parent().find('span.edit-alarm-values')[(this.selectedIndex>0?'show':'hide')]();
         });
         $(prefix+' select.edit-alarm-offset').change(function(){
-            var val = $(this).val();
-            $(this).parent().find('.edit-alarm-date, .edit-alarm-time')[val == '@' ? 'show' : 'hide']();
-            $(this).parent().find('.edit-alarm-value').prop('disabled', val === '@' || val === '0');
+            var val = $(this).val(), parent = $(this).parent();
+            parent.find('.edit-alarm-date, .edit-alarm-time')[val == '@' ? 'show' : 'hide']();
+            parent.find('.edit-alarm-value').prop('disabled', val === '@' || val === '0');
+            parent.find('.edit-alarm-related')[val == '@' ? 'hide' : 'show']();
         });
 
         $(prefix+' .edit-alarm-date').removeClass('hasDatepicker').removeAttr('id').datepicker(datepicker_settings);
 
         $(prefix).on('click', 'a.delete-alarm', function(e){
             if ($(this).closest('.edit-alarm-item').siblings().length > 0) {
                 $(this).closest('.edit-alarm-item').remove();
             }
             return false;
         });
 
         // set a unique id attribute and set label reference accordingly
         if ((index || 0) > 0 && dom_id) {
             dom_id += ':' + (new Date().getTime());
             edit_type.attr('id', dom_id);
             $(prefix+' label:first').attr('for', dom_id);
         }
 
         $(prefix).on('click', 'a.add-alarm', function(e){
             var i = $(this).closest('.edit-alarm-item').siblings().length + 1;
             var item = $(this).closest('.edit-alarm-item').clone(false)
               .removeClass('first')
               .appendTo(prefix);
 
               me.init_alarms_edit(prefix + ' .edit-alarm-item:eq(' + i + ')', i);
               $('select.edit-alarm-type, select.edit-alarm-offset', item).change();
               return false;
         });
     }
 
     this.set_alarms_edit = function(prefix, valarms)
     {
         $(prefix + ' .edit-alarm-item:gt(0)').remove();
 
         var i, alarm, domnode, val, offset;
         for (i=0; i < valarms.length; i++) {
           alarm = valarms[i];
           if (!alarm.action)
               alarm.action = 'DISPLAY';
 
           if (i == 0) {
               domnode = $(prefix + ' .edit-alarm-item').eq(0);
           }
           else {
               domnode = $(prefix + ' .edit-alarm-item').eq(0).clone(false).removeClass('first').appendTo(prefix);
               this.init_alarms_edit(prefix + ' .edit-alarm-item:eq(' + i + ')', i);
           }
 
           $('select.edit-alarm-type', domnode).val(alarm.action);
+          $('select.edit-alarm-related', domnode).val(/END/i.test(alarm.related) ? 'end' : 'start');
 
           if (String(alarm.trigger).match(/@(\d+)/)) {
               var ondate = this.fromunixtime(parseInt(RegExp.$1));
               $('select.edit-alarm-offset', domnode).val('@');
               $('input.edit-alarm-value', domnode).val('');
               $('input.edit-alarm-date', domnode).val(this.format_datetime(ondate, 1));
               $('input.edit-alarm-time', domnode).val(this.format_datetime(ondate, 2));
           }
           else if (String(alarm.trigger).match(/^[-+]*0[MHDS]$/)) {
               $('input.edit-alarm-value', domnode).val('0');
               $('select.edit-alarm-offset', domnode).val('0');
           }
           else if (String(alarm.trigger).match(/([-+])(\d+)([MHDS])/)) {
               val = RegExp.$2; offset = ''+RegExp.$1+RegExp.$3;
               $('input.edit-alarm-value', domnode).val(val);
               $('select.edit-alarm-offset', domnode).val(offset);
           }
         }
 
         // set correct visibility by triggering onchange handlers
         $(prefix + ' select.edit-alarm-type, ' + prefix + ' select.edit-alarm-offset').change();
     };
 
     this.serialize_alarms = function(prefix)
     {
         var valarms = [];
 
         $(prefix + ' .edit-alarm-item').each(function(i, elem) {
-            var val, offset, alarm = { action: $('select.edit-alarm-type', elem).val() };
+            var val, offset, alarm = {
+                    action: $('select.edit-alarm-type', elem).val(),
+                    related: $('select.edit-alarm-related', elem).val()
+                };
+
             if (alarm.action) {
                 offset = $('select.edit-alarm-offset', elem).val();
                 if (offset == '@') {
                     alarm.trigger = '@' + me.date2unixtime(me.parse_datetime($('input.edit-alarm-time', elem).val(), $('input.edit-alarm-date', elem).val()));
                 }
                 else if (offset === '0') {
                     alarm.trigger = '0S';
                 }
                 else if (!isNaN((val = parseInt($('input.edit-alarm-value', elem).val()))) && val >= 0) {
                     alarm.trigger = offset[0] + val + offset[1];
                 }
 
                 valarms.push(alarm);
             }
         });
 
         return valarms;
     };
 
 
     /*****  Alarms handling  *****/
 
     /**
      * Display a notification for the given pending alarms
      */
     this.display_alarms = function(alarms)
     {
         // clear old alert first
         if (this.alarm_dialog)
             this.alarm_dialog.dialog('destroy').remove();
 
         this.alarm_dialog = $('<div>').attr('id', 'alarm-display');
 
         var i, actions, adismiss, asnooze, alarm, html, event_ids = [], buttons = {};
         for (i=0; i < alarms.length; i++) {
             alarm = alarms[i];
             alarm.start = this.parseISO8601(alarm.start);
             alarm.end = this.parseISO8601(alarm.end);
             event_ids.push(alarm.id);
 
             html = '<h3 class="event-title">' + Q(alarm.title) + '</h3>';
             html += '<div class="event-section">' + Q(alarm.location || '') + '</div>';
             html += '<div class="event-section">' + Q(this.event_date_text(alarm)) + '</div>';
 
             adismiss = $('<a href="#" class="alarm-action-dismiss"></a>').html(rcmail.gettext('dismiss','libcalendaring')).click(function(){
                 me.dismiss_link = $(this);
                 me.dismiss_alarm(me.dismiss_link.data('id'), 0);
             });
             asnooze = $('<a href="#" class="alarm-action-snooze"></a>').html(rcmail.gettext('snooze','libcalendaring')).click(function(e){
                 me.snooze_dropdown($(this), e);
                 e.stopPropagation();
                 return false;
             });
             actions = $('<div>').addClass('alarm-actions').append(adismiss.data('id', alarm.id)).append(asnooze.data('id', alarm.id));
 
             $('<div>').addClass('alarm-item').html(html).append(actions).appendTo(this.alarm_dialog);
         }
 
         buttons[rcmail.gettext('close')] = function() {
             $(this).dialog('close');
         };
 
         buttons[rcmail.gettext('dismissall','libcalendaring')] = function() {
             // submit dismissed event_ids to server
             me.dismiss_alarm(me.alarm_ids.join(','), 0);
             $(this).dialog('close');
         };
 
         this.alarm_dialog.appendTo(document.body).dialog({
             modal: false,
             resizable: true,
             closeOnEscape: false,
             dialogClass: 'alarms',
             title: rcmail.gettext('alarmtitle','libcalendaring'),
             buttons: buttons,
             open: function() {
               setTimeout(function() {
                 me.alarm_dialog.parent().find('.ui-button:not(.ui-dialog-titlebar-close)').first().focus();
               }, 5);
             },
             close: function() {
               $('#alarm-snooze-dropdown').hide();
               $(this).dialog('destroy').remove();
               me.alarm_dialog = null;
               me.alarm_ids = null;
             },
             drag: function(event, ui) {
               $('#alarm-snooze-dropdown').hide();
             }
         });
 
         this.alarm_dialog.closest('div[role=dialog]').attr('role', 'alertdialog');
 
         this.alarm_ids = event_ids;
     };
 
     /**
      * Show a drop-down menu with a selection of snooze times
      */
     this.snooze_dropdown = function(link, event)
     {
         if (!this.snooze_popup) {
             this.snooze_popup = $('#alarm-snooze-dropdown');
             // create popup if not found
             if (!this.snooze_popup.length) {
                 this.snooze_popup = $('<div>').attr('id', 'alarm-snooze-dropdown').addClass('popupmenu').appendTo(document.body);
                 this.snooze_popup.html(rcmail.env.snooze_select)
             }
             $('#alarm-snooze-dropdown a').click(function(e){
                 var time = String(this.href).replace(/.+#/, '');
                 me.dismiss_alarm($('#alarm-snooze-dropdown').data('id'), time);
                 return false;
             });
         }
 
         // hide visible popup
         if (this.snooze_popup.is(':visible') && this.snooze_popup.data('id') == link.data('id')) {
             rcmail.command('menu-close', 'alarm-snooze-dropdown');
             this.dismiss_link = null;
         }
         else {  // open popup below the clicked link
             rcmail.command('menu-open', 'alarm-snooze-dropdown', link.get(0), event);
             this.snooze_popup.data('id', link.data('id'));
             this.dismiss_link = link;
         }
     };
 
     /**
      * Dismiss or snooze alarms for the given event
      */
     this.dismiss_alarm = function(id, snooze)
     {
         rcmail.command('menu-close', 'alarm-snooze-dropdown');
         rcmail.http_post('utils/plugin.alarms', { action:'dismiss', data:{ id:id, snooze:snooze } });
 
         // remove dismissed alarm from list
         if (this.dismiss_link) {
             this.dismiss_link.closest('div.alarm-item').hide();
             var new_ids = jQuery.grep(this.alarm_ids, function(v){ return v != id; });
             if (new_ids.length)
                 this.alarm_ids = new_ids;
             else
                 this.alarm_dialog.dialog('close');
         }
 
         this.dismiss_link = null;
     };
 
 
     /*****  Recurrence form handling  *****/
 
     /**
      * Install event handlers on recurrence form elements
      */
     this.init_recurrence_edit = function(prefix)
     {
         // toggle recurrence frequency forms
         $('#edit-recurrence-frequency').change(function(e){
             var freq = $(this).val().toLowerCase();
             $('.recurrence-form').hide();
             if (freq) {
               $('#recurrence-form-'+freq).show();
               if (freq != 'rdate')
                 $('#recurrence-form-until').show();
             }
         });
         $('#recurrence-form-rdate input.button.add').click(function(e){
             var dt, dv = $('#edit-recurrence-rdate-input').val();
             if (dv && (dt = me.parse_datetime('12:00', dv))) {
                 me.add_rdate(dt);
                 me.sort_rdates();
                 $('#edit-recurrence-rdate-input').val('')
             }
             else {
                 $('#edit-recurrence-rdate-input').select();
             }
         });
         $('#edit-recurrence-rdates').on('click', 'a.delete', function(e){
             $(this).closest('li').remove();
             return false;
         });
 
         $('#edit-recurrence-enddate').datepicker(datepicker_settings).click(function(){ $("#edit-recurrence-repeat-until").prop('checked', true) });
         $('#edit-recurrence-repeat-times').change(function(e){ $('#edit-recurrence-repeat-count').prop('checked', true); });
         $('#edit-recurrence-rdate-input').datepicker(datepicker_settings);
     };
 
     /**
      * Set recurrence form according to the given event/task record
      */
     this.set_recurrence_edit = function(rec)
     {
         var recurrence = $('#edit-recurrence-frequency').val(rec.recurrence ? rec.recurrence.FREQ || (rec.recurrence.RDATE ? 'RDATE' : '') : '').change(),
             interval = $('.recurrence-form select.edit-recurrence-interval').val(rec.recurrence ? rec.recurrence.INTERVAL || 1 : 1),
             rrtimes = $('#edit-recurrence-repeat-times').val(rec.recurrence ? rec.recurrence.COUNT || 1 : 1),
             rrenddate = $('#edit-recurrence-enddate').val(rec.recurrence && rec.recurrence.UNTIL ? this.format_datetime(this.parseISO8601(rec.recurrence.UNTIL), 1) : '');
         $('.recurrence-form input.edit-recurrence-until:checked').prop('checked', false);
         $('#edit-recurrence-rdates').html('');
 
         var weekdays = ['SU','MO','TU','WE','TH','FR','SA'],
             rrepeat_id = '#edit-recurrence-repeat-forever';
         if      (rec.recurrence && rec.recurrence.COUNT) rrepeat_id = '#edit-recurrence-repeat-count';
         else if (rec.recurrence && rec.recurrence.UNTIL) rrepeat_id = '#edit-recurrence-repeat-until';
         $(rrepeat_id).prop('checked', true);
 
         if (rec.recurrence && rec.recurrence.BYDAY && rec.recurrence.FREQ == 'WEEKLY') {
             var wdays = rec.recurrence.BYDAY.split(',');
             $('input.edit-recurrence-weekly-byday').val(wdays);
         }
         if (rec.recurrence && rec.recurrence.BYMONTHDAY) {
             $('input.edit-recurrence-monthly-bymonthday').val(String(rec.recurrence.BYMONTHDAY).split(','));
             $('input.edit-recurrence-monthly-mode').val(['BYMONTHDAY']);
         }
         if (rec.recurrence && rec.recurrence.BYDAY && (rec.recurrence.FREQ == 'MONTHLY' || rec.recurrence.FREQ == 'YEARLY')) {
             var byday, section = rec.recurrence.FREQ.toLowerCase();
             if ((byday = String(rec.recurrence.BYDAY).match(/(-?[1-4])([A-Z]+)/))) {
                 $('#edit-recurrence-'+section+'-prefix').val(byday[1]);
                 $('#edit-recurrence-'+section+'-byday').val(byday[2]);
             }
             $('input.edit-recurrence-'+section+'-mode').val(['BYDAY']);
         }
         else if (rec.start) {
             $('#edit-recurrence-monthly-byday').val(weekdays[rec.start.getDay()]);
         }
         if (rec.recurrence && rec.recurrence.BYMONTH) {
             $('input.edit-recurrence-yearly-bymonth').val(String(rec.recurrence.BYMONTH).split(','));
         }
         else if (rec.start) {
             $('input.edit-recurrence-yearly-bymonth').val([String(rec.start.getMonth()+1)]);
         }
         if (rec.recurrence && rec.recurrence.RDATE) {
             $.each(rec.recurrence.RDATE, function(i,rdate){
                 me.add_rdate(me.parseISO8601(rdate));
             });
         }
     };
 
     /**
      * Gather recurrence settings from form
      */
     this.serialize_recurrence = function(timestr)
     {
         var recurrence = '',
             freq = $('#edit-recurrence-frequency').val();
 
         if (freq != '') {
             recurrence = {
                 FREQ: freq,
                 INTERVAL: $('#edit-recurrence-interval-'+freq.toLowerCase()).val()
             };
 
             var until = $('input.edit-recurrence-until:checked').val();
             if (until == 'count')
                 recurrence.COUNT = $('#edit-recurrence-repeat-times').val();
             else if (until == 'until')
                 recurrence.UNTIL = me.date2ISO8601(me.parse_datetime(timestr || '00:00', $('#edit-recurrence-enddate').val()));
 
             if (freq == 'WEEKLY') {
                 var byday = [];
                 $('input.edit-recurrence-weekly-byday:checked').each(function(){ byday.push(this.value); });
                 if (byday.length)
                     recurrence.BYDAY = byday.join(',');
             }
             else if (freq == 'MONTHLY') {
                 var mode = $('input.edit-recurrence-monthly-mode:checked').val(), bymonday = [];
                 if (mode == 'BYMONTHDAY') {
                     $('input.edit-recurrence-monthly-bymonthday:checked').each(function(){ bymonday.push(this.value); });
                     if (bymonday.length)
                         recurrence.BYMONTHDAY = bymonday.join(',');
                 }
                 else
                     recurrence.BYDAY = $('#edit-recurrence-monthly-prefix').val() + $('#edit-recurrence-monthly-byday').val();
             }
             else if (freq == 'YEARLY') {
                 var byday, bymonth = [];
                 $('input.edit-recurrence-yearly-bymonth:checked').each(function(){ bymonth.push(this.value); });
                 if (bymonth.length)
                     recurrence.BYMONTH = bymonth.join(',');
                 if ((byday = $('#edit-recurrence-yearly-byday').val()))
                     recurrence.BYDAY = $('#edit-recurrence-yearly-prefix').val() + byday;
             }
             else if (freq == 'RDATE') {
                 recurrence = { RDATE:[] };
                 // take selected but not yet added date into account
                 if ($('#edit-recurrence-rdate-input').val() != '') {
                     $('#recurrence-form-rdate input.button.add').click();
                 }
                 $('#edit-recurrence-rdates li').each(function(i, li){
                     recurrence.RDATE.push($(li).attr('data-value'));
                 });
             }
         }
 
         return recurrence;
     };
 
     // add the given date to the RDATE list
     this.add_rdate = function(date)
     {
         var li = $('<li>')
             .attr('data-value', this.date2ISO8601(date))
             .html('<span>' + Q(this.format_datetime(date, 1)) + '</span>')
             .appendTo('#edit-recurrence-rdates');
 
         $('<a>').attr('href', '#del')
             .addClass('iconbutton delete')
             .html(rcmail.get_label('delete', 'libcalendaring'))
             .attr('title', rcmail.get_label('delete', 'libcalendaring'))
             .appendTo(li);
     };
 
     // re-sort the list items by their 'data-value' attribute
     this.sort_rdates = function()
     {
         var mylist = $('#edit-recurrence-rdates'),
             listitems = mylist.children('li').get();
         listitems.sort(function(a, b) {
             var compA = $(a).attr('data-value');
             var compB = $(b).attr('data-value');
             return (compA < compB) ? -1 : (compA > compB) ? 1 : 0;
         })
         $.each(listitems, function(idx, item) { mylist.append(item); });
     };
 
 
     /*****  Attendee form handling  *****/
 
     // expand the given contact group into individual event/task attendees
     this.expand_attendee_group = function(e, add, remove)
     {
         var id = (e.data ? e.data.email : null) || $(e.target).attr('data-email'),
             role_select = $(e.target).closest('tr').find('select.edit-attendee-role option:selected');
 
         this.group2expand[id] = { link: e.target, data: $.extend({}, e.data || {}), adder: add, remover: remove }
 
         // copy group role from the according form element
         if (role_select.length) {
             this.group2expand[id].data.role = role_select.val();
         }
 
         // register callback handler
         if (!this._expand_attendee_listener) {
             this._expand_attendee_listener = this.expand_attendee_callback;
             rcmail.addEventListener('plugin.expand_attendee_callback', function(result) {
                 me._expand_attendee_listener(result);
             });
         }
 
         rcmail.http_post('libcal/plugin.expand_attendee_group', { id: id, data: e.data || {} }, rcmail.set_busy(true, 'loading'));
     };
 
     // callback from server to expand an attendee group
     this.expand_attendee_callback = function(result)
     {
         var attendee, id = result.id,
             data = this.group2expand[id],
             row = $(data.link).closest('tr');
 
         // replace group entry with all members returned by the server
         if (data && data.adder && result.members && result.members.length) {
             for (var i=0; i < result.members.length; i++) {
                 attendee = result.members[i];
                 attendee.role = data.data.role;
                 attendee.cutype = 'INDIVIDUAL';
                 attendee.status = 'NEEDS-ACTION';
                 data.adder(attendee, null, row);
             }
 
             if (data.remover) {
                 data.remover(data.link, id)
             }
             else {
                 row.remove();
             }
 
             delete this.group2expand[id];
         }
         else {
             rcmail.display_message(result.error || rcmail.gettext('expandattendeegroupnodata','libcalendaring'), 'error');
         }
     };
 
 
     // Render message reference links to the given container
     this.render_message_links = function(links, container, edit, plugin)
     {
         var ul = $('<ul>').addClass('attachmentslist');
 
         $.each(links, function(i, link) {
             if (!link.mailurl)
                 return true;  // continue
 
             var li = $('<li>').addClass('link')
                 .addClass('message eml')
                 .append($('<a>')
                     .attr('href', link.mailurl)
                     .addClass('messagelink')
                     .text(link.subject || link.uri)
                 )
                 .appendTo(ul);
 
             // add icon to remove the link
             if (edit) {
                 $('<a>')
                     .attr('href', '#delete')
                     .attr('title', rcmail.gettext('removelink', plugin))
                     .attr('data-uri', link.uri)
                     .addClass('delete')
                     .text(rcmail.gettext('delete'))
                     .appendTo(li);
             }
         });
 
         container.empty().append(ul);
     }
 }
 
 //////  static methods
 
 /**
  *
  */
 rcube_libcalendaring.add_from_itip_mail = function(mime_id, task, status, dom_id)
 {
     // ask user to delete the declined event from the local calendar (#1670)
     var del = false;
     if (rcmail.env.rsvp_saved && status == 'declined') {
         del = confirm(rcmail.gettext('itip.declinedeleteconfirm'));
     }
 
     // open dialog for iTip delegation
     if (status == 'delegated') {
         rcube_libcalendaring.itip_delegate_dialog(function(data) {
             rcmail.http_post(task + '/itip-delegate', {
                 _uid: rcmail.env.uid,
                 _mbox: rcmail.env.mailbox,
                 _part: mime_id,
                 _to: data.to,
                 _rsvp: data.rsvp ? 1 : 0,
                 _comment: data.comment,
                 _folder: data.target
             }, rcmail.set_busy(true, 'itip.savingdata'));
         }, $('#rsvp-'+dom_id+' .folder-select'));
         return false;
     }
 
     var noreply = 0, comment = '';
     if (dom_id) {
       noreply = $('#noreply-'+dom_id+':checked').length ? 1 : 0;
       if (!noreply)
         comment = $('#reply-comment-'+dom_id).val();
     }
 
     rcmail.http_post(task + '/mailimportitip', {
         _uid: rcmail.env.uid,
         _mbox: rcmail.env.mailbox,
         _part: mime_id,
         _folder: $('#itip-saveto').val(),
         _status: status,
         _del: del?1:0,
         _noreply: noreply,
         _comment: comment
       }, rcmail.set_busy(true, 'itip.savingdata'));
 
     return false;
 };
 
 /**
  * Helper function to render the iTip delegation dialog
  * and trigger a callback function when submitted.
  */
 rcube_libcalendaring.itip_delegate_dialog = function(callback, selector)
 {
     // show dialog for entering the delegatee address and comment
     var html = '<form class="itip-dialog-form" action="javascript:void()">' +
         '<div class="form-section">' +
             '<label for="itip-delegate-to">' + rcmail.gettext('itip.delegateto') + '</label><br/>' +
             '<input type="text" id="itip-delegate-to" class="text" size="40" value="" />' +
         '</div>' +
         '<div class="form-section">' +
             '<label for="itip-delegate-rsvp">' +
                 '<input type="checkbox" id="itip-delegate-rsvp" class="checkbox" size="40" value="" />' +
                 rcmail.gettext('itip.delegatersvpme') +
             '</label>' +
         '</div>' +
         '<div class="form-section">' +
             '<textarea id="itip-delegate-comment" class="itip-comment" cols="40" rows="8" placeholder="' +
                 rcmail.gettext('itip.itipcomment') + '"></textarea>' + 
         '</div>' +
         '<div class="form-section">' +
             (selector && selector.length ? selector.html() : '') +
         '</div>' +
     '</form>';
 
     var dialog, buttons = [];
     buttons.push({
         text: rcmail.gettext('itipdelegated', 'itip'),
         click: function() {
             var doc = window.parent.document,
                 delegatee = String($('#itip-delegate-to', doc).val()).replace(/(^\s+)|(\s+$)/, '');
 
             if (delegatee != '' && rcube_check_email(delegatee, true)) {
                 callback({
                     to: delegatee,
                     rsvp: $('#itip-delegate-rsvp', doc).prop('checked'),
                     comment: $('#itip-delegate-comment', doc).val(),
                     target: $('#itip-saveto', doc).val()
                 });
 
                 setTimeout(function() { dialog.dialog("close"); }, 500);
             }
             else {
                 alert(rcmail.gettext('itip.delegateinvalidaddress'));
                 $('#itip-delegate-to', doc).focus();
             }
         }
     });
 
     buttons.push({
         text: rcmail.gettext('cancel', 'itip'),
         click: function() {
             dialog.dialog('close');
         }
     });
 
     dialog = rcmail.show_popup_dialog(html, rcmail.gettext('delegateinvitation', 'itip'), buttons, {
         width: 460,
         open: function(event, ui) {
             $(this).parent().find('.ui-button:not(.ui-dialog-titlebar-close)').first().addClass('mainaction');
             $(this).find('#itip-saveto').val('');
 
             // initialize autocompletion
             var ac_props, rcm = rcmail.is_framed() ? parent.rcmail : rcmail;
             if (rcmail.env.autocomplete_threads > 0) {
                 ac_props = {
                     threads: rcmail.env.autocomplete_threads,
                     sources: rcmail.env.autocomplete_sources
                 };
             }
             rcm.init_address_input_events($(this).find('#itip-delegate-to').focus(), ac_props);
             rcm.env.recipients_delimiter = '';
         },
         close: function(event, ui) {
             rcm = rcmail.is_framed() ? parent.rcmail : rcmail;
             rcm.ksearch_blur();
             $(this).remove();
         }
     });
 
     return dialog;
 };
 
 /**
  * Show a menu for selecting the RSVP reply mode
  */
 rcube_libcalendaring.itip_rsvp_recurring = function(btn, callback)
 {
     var mnu = $('<ul></ul>').addClass('popupmenu libcal-rsvp-replymode');
 
     $.each(['all','current'/*,'future'*/], function(i, mode) {
         $('<li><a>' + rcmail.get_label('rsvpmode'+mode, 'libcalendaring') + '</a>')
         .addClass('ui-menu-item')
         .attr('rel', mode)
         .appendTo(mnu);
     });
 
     var action = btn.attr('rel');
 
     // open the mennu
     mnu.menu({
         select: function(event, ui) {
             callback(action, ui.item.attr('rel'));
         }
     })
     .appendTo(document.body)
     .position({ my: 'left top', at: 'left bottom+2', of: btn })
     .data('action', action);
 
     setTimeout(function() {
         $(document).one('click', function() {
             mnu.menu('destroy');
             mnu.remove();
         });
     }, 100);
 };
 
 /**
  *
  */
 rcube_libcalendaring.remove_from_itip = function(event, task, title)
 {
     if (confirm(rcmail.gettext('itip.deleteobjectconfirm').replace('$title', title))) {
         rcmail.http_post(task + '/itip-remove',
             event,
             rcmail.set_busy(true, 'itip.savingdata')
         );
     }
 };
 
 /**
  *
  */
 rcube_libcalendaring.decline_attendee_reply = function(mime_id, task)
 {
     // show dialog for entering a comment and send to server
     var html = '<div class="itip-dialog-confirm-text">' + rcmail.gettext('itip.declineattendeeconfirm') + '</div>' +
         '<textarea id="itip-decline-comment" class="itip-comment" cols="40" rows="8"></textarea>';
 
     var dialog, buttons = [];
     buttons.push({
         text: rcmail.gettext('declineattendee', 'itip'),
         click: function() {
             rcmail.http_post(task + '/itip-decline-reply', {
                 _uid: rcmail.env.uid,
                 _mbox: rcmail.env.mailbox,
                 _part: mime_id,
                 _comment: $('#itip-decline-comment', window.parent.document).val()
             }, rcmail.set_busy(true, 'itip.savingdata'));
           dialog.dialog("close");
         }
     });
 
     buttons.push({
         text: rcmail.gettext('cancel', 'itip'),
         click: function() {
           dialog.dialog('close');
         }
     });
 
     dialog = rcmail.show_popup_dialog(html, rcmail.gettext('declineattendee', 'itip'), buttons, {
         width: 460,
         open: function() {
             $(this).parent().find('.ui-button:not(.ui-dialog-titlebar-close)').first().addClass('mainaction');
             $('#itip-decline-comment').focus();
         }
     });
 
     return false;
 };
 
 /**
  *
  */
 rcube_libcalendaring.fetch_itip_object_status = function(p)
 {
   rcmail.http_post(p.task + '/itip-status', { data: p });
 };
 
 /**
  *
  */
 rcube_libcalendaring.update_itip_object_status = function(p)
 {
   rcmail.env.rsvp_saved = p.saved;
   rcmail.env.itip_existing = p.existing;
 
   // hide all elements first
   $('#itip-buttons-'+p.id+' > div').hide();
   $('#rsvp-'+p.id+' .folder-select').remove();
 
   if (p.html) {
     // append/replace rsvp status display
     $('#loading-'+p.id).next('.rsvp-status').remove();
     $('#loading-'+p.id).hide().after(p.html);
   }
 
   // enable/disable rsvp buttons
   if (p.action == 'rsvp') {
     $('#rsvp-'+p.id+' input.button').prop('disabled', false)
       .filter('.'+String(p.status||'unknown').toLowerCase()).prop('disabled', p.latest);
   }
  
   // show rsvp/import buttons (with calendar selector)
   $('#'+p.action+'-'+p.id).show().find('input.button').last().after(p.select);
 
   // show itip box appendix after replacing the given placeholders
   if (p.append && p.append.selector) {
     var elem = $(p.append.selector);
     if (p.append.replacements) {
       $.each(p.append.replacements, function(k, html) {
         elem.html(elem.html().replace(k, html));
       });
     }
     else if (p.append.html) {
       elem.html(p.append.html)
     }
     elem.show();
   }
 };
 
 /**
  * Callback from server after an iTip message has been processed
  */
 rcube_libcalendaring.itip_message_processed = function(metadata)
 {
   if (metadata.after_action) {
     setTimeout(function(){ rcube_libcalendaring.itip_after_action(metadata.after_action); }, 1200);
   }
   else {
     rcube_libcalendaring.fetch_itip_object_status(metadata);
   }
 };
 
 /**
  * After-action on iTip request message. Action types:
  *     0 - no action
  *     1 - move to Trash
  *     2 - delete the message
  *     3 - flag as deleted
  *     folder_name - move the message to the specified folder
  */
 rcube_libcalendaring.itip_after_action = function(action)
 {
   if (!action) {
     return;
   }
 
   var rc = rcmail.is_framed() ? parent.rcmail : rcmail;
 
   if (action === 2) {
     rc.permanently_remove_messages();
   }
   else if (action === 3) {
     rc.mark_message('delete');
   }
   else {
     rc.move_messages(action === 1 ? rc.env.trash_mailbox : action);
   }
 };
 
 /**
  * Open the calendar preview for the current iTip event
  */
 rcube_libcalendaring.open_itip_preview = function(url, msgref)
 {
   if (!rcmail.env.itip_existing)
     url += '&itip=' + escape(msgref);
 
   var win = rcmail.open_window(url);
 };
 
 
 // extend jQuery
 (function($){
   $.fn.serializeJSON = function(){
     var json = {};
     jQuery.map($(this).serializeArray(), function(n, i) {
       json[n['name']] = n['value'];
     });
     return json;
   };
 })(jQuery);
 
 
 /* libcalendaring plugin initialization */
 window.rcmail && rcmail.addEventListener('init', function(evt) {
   if (rcmail.env.libcal_settings) {
     var libcal = new rcube_libcalendaring(rcmail.env.libcal_settings);
     rcmail.addEventListener('plugin.display_alarms', function(alarms){ libcal.display_alarms(alarms); });
   }
 
   rcmail.addEventListener('plugin.update_itip_object_status', rcube_libcalendaring.update_itip_object_status)
     .addEventListener('plugin.fetch_itip_object_status', rcube_libcalendaring.fetch_itip_object_status)
     .addEventListener('plugin.itip_message_processed', rcube_libcalendaring.itip_message_processed);
 
   $('.rsvp-buttons').on('click', 'a.reply-comment-toggle', function(e){
     $(this).hide().parent().find('textarea').show().focus();
     return false;
   });
 
   if (rcmail.env.action == 'get-attachment' && rcmail.gui_objects['attachmentframe']) {
     rcmail.register_command('print-attachment', function() {
       var frame = rcmail.get_frame_window(rcmail.gui_objects['attachmentframe'].id);
       if (frame) frame.print();
     }, true);
   }
 
   if (rcmail.env.action == 'get-attachment' && rcmail.env.attachment_download_url) {
     rcmail.register_command('download-attachment', function() {
       rcmail.location_href(rcmail.env.attachment_download_url, window);
     }, true);
   }
 
 });
diff --git a/plugins/libcalendaring/libcalendaring.php b/plugins/libcalendaring/libcalendaring.php
index 4246fa7f..ddbebe43 100644
--- a/plugins/libcalendaring/libcalendaring.php
+++ b/plugins/libcalendaring/libcalendaring.php
@@ -1,1640 +1,1650 @@
 <?php
 
 /**
  * Library providing common functions for calendaring plugins
  *
  * Provides utility functions for calendar-related modules such as
  * - alarms display and dismissal
  * - attachment handling
  * - recurrence computation and UI elements
  * - ical parsing and exporting
  * - itip scheduling protocol
  *
  * @version @package_version@
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2012-2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 class libcalendaring extends rcube_plugin
 {
     public $rc;
     public $timezone;
     public $gmt_offset;
     public $dst_active;
     public $timezone_offset;
     public $ical_parts = array();
     public $ical_message;
 
     public $defaults = array(
       'calendar_date_format'  => "yyyy-MM-dd",
       'calendar_date_short'   => "M-d",
       'calendar_date_long'    => "MMM d yyyy",
       'calendar_date_agenda'  => "ddd MM-dd",
       'calendar_time_format'  => "HH:mm",
       'calendar_first_day'    => 1,
       'calendar_first_hour'   => 6,
       'calendar_date_format_sets' => array(
         'yyyy-MM-dd' => array('MMM d yyyy',   'M-d',  'ddd MM-dd'),
         'dd-MM-yyyy' => array('d MMM yyyy',   'd-M',  'ddd dd-MM'),
         'yyyy/MM/dd' => array('MMM d yyyy',   'M/d',  'ddd MM/dd'),
         'MM/dd/yyyy' => array('MMM d yyyy',   'M/d',  'ddd MM/dd'),
         'dd/MM/yyyy' => array('d MMM yyyy',   'd/M',  'ddd dd/MM'),
         'dd.MM.yyyy' => array('dd. MMM yyyy', 'd.M',  'ddd dd.MM.'),
         'd.M.yyyy'   => array('d. MMM yyyy',  'd.M',  'ddd d.MM.'),
       ),
     );
 
     private static $instance;
     private static $email_regex = '/([a-z0-9][a-z0-9\-\.\+\_]*@[^&@"\'.][^@&"\']*\\.([^\\x00-\\x40\\x5b-\\x60\\x7b-\\x7f]{2,}|xn--[a-z0-9]{2,}))/';
 
     private $mail_ical_parser;
 
     /**
      * Singleton getter to allow direct access from other plugins
      */
     public static function get_instance()
     {
         return self::$instance;
     }
 
     /**
      * Required plugin startup method
      */
     public function init()
     {
         self::$instance = $this;
 
         $this->rc = rcube::get_instance();
 
         // set user's timezone
         try {
             $this->timezone = new DateTimeZone($this->rc->config->get('timezone', 'GMT'));
         }
         catch (Exception $e) {
             $this->timezone = new DateTimeZone('GMT');
         }
 
         $now = new DateTime('now', $this->timezone);
 
         $this->gmt_offset      = $now->getOffset();
         $this->dst_active      = $now->format('I');
         $this->timezone_offset = $this->gmt_offset / 3600 - $this->dst_active;
 
         $this->add_texts('localization/', false);
 
         // include client scripts and styles
         if ($this->rc->output) {
             // add hook to display alarms
             $this->add_hook('refresh', array($this, 'refresh'));
             $this->register_action('plugin.alarms', array($this, 'alarms_action'));
             $this->register_action('plugin.expand_attendee_group', array($this, 'expand_attendee_group'));
         }
 
         // proceed initialization in startup hook
         $this->add_hook('startup', array($this, 'startup'));
     }
 
     /**
      * Startup hook
      */
     public function startup($args)
     {
         if ($this->rc->output && $this->rc->output->type == 'html') {
             $this->rc->output->set_env('libcal_settings', $this->load_settings());
             $this->include_script('libcalendaring.js');
             $this->include_stylesheet($this->local_skin_path() . '/libcal.css');
         }
 
         if ($args['task'] == 'mail') {
             if ($args['action'] == 'show' || $args['action'] == 'preview') {
                 $this->add_hook('message_load', array($this, 'mail_message_load'));
             }
         }
     }
 
     /**
      * Load iCalendar functions
      */
     public static function get_ical()
     {
         $self = self::get_instance();
         require_once($self->home . '/libvcalendar.php');
         return new libvcalendar();
     }
 
     /**
      * Load iTip functions
      */
     public static function get_itip($domain = 'libcalendaring')
     {
         $self = self::get_instance();
         require_once($self->home . '/lib/libcalendaring_itip.php');
         return new libcalendaring_itip($self, $domain);
     }
 
     /**
      * Load recurrence computation engine
      */
     public static function get_recurrence()
     {
         $self = self::get_instance();
         require_once($self->home . '/lib/libcalendaring_recurrence.php');
         return new libcalendaring_recurrence($self);
     }
 
     /**
      * Shift dates into user's current timezone
      *
      * @param mixed Any kind of a date representation (DateTime object, string or unix timestamp)
      * @return object DateTime object in user's timezone
      */
     public function adjust_timezone($dt, $dateonly = false)
     {
         if (is_numeric($dt))
             $dt = new DateTime('@'.$dt);
         else if (is_string($dt))
             $dt = rcube_utils::anytodatetime($dt);
 
         if ($dt instanceof DateTime && !($dt->_dateonly || $dateonly)) {
             $dt->setTimezone($this->timezone);
         }
 
         return $dt;
     }
 
 
     /**
      *
      */
     public function load_settings()
     {
         $this->date_format_defaults();
         $settings = array();
 
         // configuration
         $settings['date_format'] = (string)$this->rc->config->get('calendar_date_format', $this->defaults['calendar_date_format']);
         $settings['time_format'] = (string)$this->rc->config->get('calendar_time_format', $this->defaults['calendar_time_format']);
         $settings['date_short']  = (string)$this->rc->config->get('calendar_date_short', $this->defaults['calendar_date_short']);
         $settings['date_long']   = (string)$this->rc->config->get('calendar_date_long', $this->defaults['calendar_date_long']);
         $settings['dates_long']  = str_replace(' yyyy', '[ yyyy]', $settings['date_long']) . "{ '&mdash;' " . $settings['date_long'] . '}';
         $settings['first_day']   = (int)$this->rc->config->get('calendar_first_day', $this->defaults['calendar_first_day']);
 
         $settings['timezone'] = $this->timezone_offset;
         $settings['dst'] = $this->dst_active;
 
         // localization
         $settings['days'] = array(
             $this->rc->gettext('sunday'),   $this->rc->gettext('monday'),
             $this->rc->gettext('tuesday'),  $this->rc->gettext('wednesday'),
             $this->rc->gettext('thursday'), $this->rc->gettext('friday'),
             $this->rc->gettext('saturday')
         );
         $settings['days_short'] = array(
             $this->rc->gettext('sun'), $this->rc->gettext('mon'),
             $this->rc->gettext('tue'), $this->rc->gettext('wed'),
             $this->rc->gettext('thu'), $this->rc->gettext('fri'),
             $this->rc->gettext('sat')
         );
         $settings['months'] = array(
             $this->rc->gettext('longjan'), $this->rc->gettext('longfeb'),
             $this->rc->gettext('longmar'), $this->rc->gettext('longapr'),
             $this->rc->gettext('longmay'), $this->rc->gettext('longjun'),
             $this->rc->gettext('longjul'), $this->rc->gettext('longaug'),
             $this->rc->gettext('longsep'), $this->rc->gettext('longoct'),
             $this->rc->gettext('longnov'), $this->rc->gettext('longdec')
         );
         $settings['months_short'] = array(
             $this->rc->gettext('jan'), $this->rc->gettext('feb'),
             $this->rc->gettext('mar'), $this->rc->gettext('apr'),
             $this->rc->gettext('may'), $this->rc->gettext('jun'),
             $this->rc->gettext('jul'), $this->rc->gettext('aug'),
             $this->rc->gettext('sep'), $this->rc->gettext('oct'),
             $this->rc->gettext('nov'), $this->rc->gettext('dec')
         );
         $settings['today'] = $this->rc->gettext('today');
 
         // define list of file types which can be displayed inline
         // same as in program/steps/mail/show.inc
         $settings['mimetypes'] = (array)$this->rc->config->get('client_mimetypes');
 
         return $settings;
     }
 
 
     /**
      * Helper function to set date/time format according to config and user preferences
      */
     private function date_format_defaults()
     {
         static $defaults = array();
 
         // nothing to be done
         if (isset($defaults['date_format']))
           return;
 
         $defaults['date_format'] = $this->rc->config->get('calendar_date_format', self::from_php_date_format($this->rc->config->get('date_format')));
         $defaults['time_format'] = $this->rc->config->get('calendar_time_format', self::from_php_date_format($this->rc->config->get('time_format')));
 
         // override defaults
         if ($defaults['date_format'])
             $this->defaults['calendar_date_format'] = $defaults['date_format'];
         if ($defaults['time_format'])
             $this->defaults['calendar_time_format'] = $defaults['time_format'];
 
         // derive format variants from basic date format
         $format_sets = $this->rc->config->get('calendar_date_format_sets', $this->defaults['calendar_date_format_sets']);
         if ($format_set = $format_sets[$this->defaults['calendar_date_format']]) {
             $this->defaults['calendar_date_long'] = $format_set[0];
             $this->defaults['calendar_date_short'] = $format_set[1];
             $this->defaults['calendar_date_agenda'] = $format_set[2];
         }
     }
 
     /**
      * Compose a date string for the given event
      */
     public function event_date_text($event, $tzinfo = false)
     {
         $fromto = '--';
 
         // handle task objects
         if ($event['_type'] == 'task' && is_object($event['due'])) {
             $date_format = $event['due']->_dateonly ? self::to_php_date_format($this->rc->config->get('calendar_date_format', $this->defaults['calendar_date_format'])) : null;
             $fromto = $this->rc->format_date($event['due'], $date_format, false);
 
             // add timezone information
             if ($fromto && $tzinfo && ($tzname = $this->timezone->getName())) {
                 $fromto .= ' (' . strtr($tzname, '_', ' ') . ')';
             }
 
             return $fromto;
         }
 
         // abort if no valid event dates are given
         if (!is_object($event['start']) || !is_a($event['start'], 'DateTime') || !is_object($event['end']) || !is_a($event['end'], 'DateTime')) {
             return $fromto;
         }
 
         $duration = $event['start']->diff($event['end'])->format('s');
 
         $this->date_format_defaults();
         $date_format = self::to_php_date_format($this->rc->config->get('calendar_date_format', $this->defaults['calendar_date_format']));
         $time_format = self::to_php_date_format($this->rc->config->get('calendar_time_format', $this->defaults['calendar_time_format']));
 
         if ($event['allday']) {
             $fromto = format_date($event['start'], $date_format);
             if (($todate = format_date($event['end'], $date_format)) != $fromto)
                 $fromto .= ' - ' . $todate;
         }
         else if ($duration < 86400 && $event['start']->format('d') == $event['end']->format('d')) {
             $fromto = format_date($event['start'], $date_format) . ' ' . format_date($event['start'], $time_format) .
                 ' - ' . format_date($event['end'], $time_format);
         }
         else {
             $fromto = format_date($event['start'], $date_format) . ' ' . format_date($event['start'], $time_format) .
                 ' - ' . format_date($event['end'], $date_format) . ' ' . format_date($event['end'], $time_format);
         }
 
         // add timezone information
         if ($tzinfo && ($tzname = $this->timezone->getName())) {
             $fromto .= ' (' . strtr($tzname, '_', ' ') . ')';
         }
 
         return $fromto;
     }
 
 
     /**
      * Render HTML form for alarm configuration
      */
     public function alarm_select($attrib, $alarm_types, $absolute_time = true)
     {
         unset($attrib['name']);
 
         $input_value = new html_inputfield(array('name' => 'alarmvalue[]', 'class' => 'edit-alarm-value', 'size' => 3));
         $input_date  = new html_inputfield(array('name' => 'alarmdate[]', 'class' => 'edit-alarm-date', 'size' => 10));
         $input_time  = new html_inputfield(array('name' => 'alarmtime[]', 'class' => 'edit-alarm-time', 'size' => 6));
-        $select_type   = new html_select(array('name' => 'alarmtype[]', 'class' => 'edit-alarm-type', 'id' => $attrib['id']));
-        $select_offset = new html_select(array('name' => 'alarmoffset[]', 'class' => 'edit-alarm-offset'));
+        $select_type    = new html_select(array('name' => 'alarmtype[]', 'class' => 'edit-alarm-type', 'id' => $attrib['id']));
+        $select_offset  = new html_select(array('name' => 'alarmoffset[]', 'class' => 'edit-alarm-offset'));
+        $select_related = new html_select(array('name' => 'alarmrelated[]', 'class' => 'edit-alarm-related'));
+        $object_type    = $attrib['_type'] ?: 'event';
 
         $select_type->add($this->gettext('none'), '');
         foreach ($alarm_types as $type)
             $select_type->add($this->gettext(strtolower("alarm{$type}option")), $type);
 
         foreach (array('-M','-H','-D','+M','+H','+D') as $trigger)
             $select_offset->add($this->gettext('trigger' . $trigger), $trigger);
 
         $select_offset->add($this->gettext('trigger0'), '0');
         if ($absolute_time)
             $select_offset->add($this->gettext('trigger@'), '@');
 
+        $select_related->add($this->gettext('relatedstart'), 'start');
+        $select_related->add($this->gettext('relatedend' . $object_type), 'end');
+
         // pre-set with default values from user settings
         $preset = self::parse_alarm_value($this->rc->config->get('calendar_default_alarm_offset', '-15M'));
         $hidden = array('style' => 'display:none');
         $html = html::span('edit-alarm-set',
             $select_type->show($this->rc->config->get('calendar_default_alarm_type', '')) . ' ' .
             html::span(array('class' => 'edit-alarm-values', 'style' => 'display:none'),
                 $input_value->show($preset[0]) . ' ' .
                 $select_offset->show($preset[1]) . ' ' .
+                $select_related->show() . ' ' .
                 $input_date->show('', $hidden) . ' ' .
                 $input_time->show('', $hidden)
             )
         );
 
         // TODO: support adding more alarms
         #$html .= html::a(array('href' => '#', 'id' => 'edit-alam-add', 'title' => $this->gettext('addalarm')),
         #  $attrib['addicon'] ? html::img(array('src' => $attrib['addicon'], 'alt' => 'add')) : '(+)');
 
         return $html;
     }
 
     /**
      * Get a list of email addresses of the given user (from login and identities)
      *
      * @param string User Email (default to current user)
      * @return array Email addresses related to the user
      */
     public function get_user_emails($user = null)
     {
         static $_emails = array();
 
         if (empty($user)) {
             $user = $this->rc->user->get_username();
         }
 
         // return cached result
         if (is_array($_emails[$user])) {
             return $_emails[$user];
         }
 
         $emails = array($user);
         $plugin = $this->rc->plugins->exec_hook('calendar_user_emails', array('emails' => $emails));
         $emails = array_map('strtolower', $plugin['emails']);
 
         // add all emails from the current user's identities
         if (!$plugin['abort'] && ($user == $this->rc->user->get_username())) {
             foreach ($this->rc->user->list_emails() as $identity) {
                 $emails[] = strtolower($identity['email']);
             }
         }
 
         $_emails[$user] = array_unique($emails);
         return $_emails[$user];
     }
 
     /**
      * Set the given participant status to the attendee matching the current user's identities
      *
      * @param array   Hash array with event struct
      * @param string  The PARTSTAT value to set
      * @return mixed  Email address of the updated attendee or False if none matching found
      */
     public function set_partstat(&$event, $status, $recursive = true)
     {
         $success = false;
         $emails = $this->get_user_emails();
         foreach ((array)$event['attendees'] as $i => $attendee) {
             if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
                 $event['attendees'][$i]['status'] = strtoupper($status);
                 $success = $attendee['email'];
             }
         }
 
         // apply partstat update to each existing exception
         if ($event['recurrence'] && is_array($event['recurrence']['EXCEPTIONS'])) {
             foreach ($event['recurrence']['EXCEPTIONS'] as $i => $exception) {
                 $this->set_partstat($event['recurrence']['EXCEPTIONS'][$i], $status, false);
             }
 
             // set link to top-level exceptions
             $event['exceptions'] = &$event['recurrence']['EXCEPTIONS'];
         }
 
         return $success;
     }
 
 
     /*********  Alarms handling  *********/
 
     /**
      * Helper function to convert alarm trigger strings
      * into two-field values (e.g. "-45M" => 45, "-M")
      */
     public static function parse_alarm_value($val)
     {
         if ($val[0] == '@') {
             return array(new DateTime($val));
         }
         else if (preg_match('/([+-]?)P?(T?\d+[HMSDW])+/', $val, $m) && preg_match_all('/T?(\d+)([HMSDW])/', $val, $m2, PREG_SET_ORDER)) {
             if ($m[1] == '')
                 $m[1] = '+';
             foreach ($m2 as $seg) {
                 $prefix = $seg[2] == 'D' || $seg[2] == 'W' ? 'P' : 'PT';
                 if ($seg[1] > 0) {  // ignore zero values
                     // convert seconds to minutes
                     if ($seg[2] == 'S') {
                         $seg[2] = 'M';
                         $seg[1] = max(1, round($seg[1]/60));
                     }
 
                     return array($seg[1], $m[1].$seg[2], $m[1].$seg[1].$seg[2], $m[1].$prefix.$seg[1].$seg[2]);
                 }
             }
 
             // return zero value nevertheless
             return array($seg[1], $m[1].$seg[2], $m[1].$seg[1].$seg[2], $m[1].$prefix.$seg[1].$seg[2]);
         }
 
         return false;
     }
 
     /**
      * Convert the alarms list items to be processed on the client
      */
     public static function to_client_alarms($valarms)
     {
         return array_map(function($alarm){
             if ($alarm['trigger'] instanceof DateTime) {
                 $alarm['trigger'] = '@' . $alarm['trigger']->format('U');
             }
             else if ($trigger = libcalendaring::parse_alarm_value($alarm['trigger'])) {
                 $alarm['trigger'] = $trigger[2];
             }
             return $alarm;
         }, (array)$valarms);
     }
 
     /**
      * Process the alarms values submitted by the client
      */
     public static function from_client_alarms($valarms)
     {
         return array_map(function($alarm){
             if ($alarm['trigger'][0] == '@') {
                 try {
                     $alarm['trigger'] = new DateTime($alarm['trigger']);
                     $alarm['trigger']->setTimezone(new DateTimeZone('UTC'));
                 }
                 catch (Exception $e) { /* handle this ? */ }
             }
             else if ($trigger = libcalendaring::parse_alarm_value($alarm['trigger'])) {
                 $alarm['trigger'] = $trigger[3];
             }
             return $alarm;
         }, (array)$valarms);
     }
 
     /**
      * Render localized text for alarm settings
      */
     public static function alarms_text($alarms)
     {
         if (is_array($alarms) && is_array($alarms[0])) {
             $texts = array();
             foreach ($alarms as $alarm) {
                 if ($text = self::alarm_text($alarm))
                     $texts[] = $text;
             }
 
             return join(', ', $texts);
         }
         else {
             return self::alarm_text($alarms);
         }
     }
 
     /**
      * Render localized text for a single alarm property
      */
     public static function alarm_text($alarm)
     {
         if (is_string($alarm)) {
             list($trigger, $action) = explode(':', $alarm);
         }
         else {
             $trigger = $alarm['trigger'];
-            $action = $alarm['action'];
+            $action  = $alarm['action'];
+            $related = $alarm['related'];
         }
 
-        $text = '';
+        $text  = '';
         $rcube = rcube::get_instance();
 
         switch ($action) {
         case 'EMAIL':
             $text = $rcube->gettext('libcalendaring.alarmemail');
             break;
         case 'DISPLAY':
             $text = $rcube->gettext('libcalendaring.alarmdisplay');
             break;
         case 'AUDIO':
             $text = $rcube->gettext('libcalendaring.alarmaudio');
             break;
         }
 
         if ($trigger instanceof DateTime) {
             $text .= ' ' . $rcube->gettext(array(
                 'name' => 'libcalendaring.alarmat',
                 'vars' => array('datetime' => $rcube->format_date($trigger))
             ));
         }
         else if (preg_match('/@(\d+)/', $trigger, $m)) {
             $text .= ' ' . $rcube->gettext(array(
                 'name' => 'libcalendaring.alarmat',
                 'vars' => array('datetime' => $rcube->format_date($m[1]))
             ));
         }
         else if ($val = self::parse_alarm_value($trigger)) {
+            $r = strtoupper($related ?: 'start') == 'END' ? 'end' : '';
             // TODO: for all-day events say 'on date of event at XX' ?
-            if ($val[0] == 0)
-                $text .= ' ' . $rcube->gettext('libcalendaring.triggerattime');
-            else
-                $text .= ' ' . intval($val[0]) . ' ' . $rcube->gettext('libcalendaring.trigger' . $val[1]);
+            if ($val[0] == 0) {
+                $text .= ' ' . $rcube->gettext('libcalendaring.triggerattime' . $r);
+            }
+            else {
+                $label = 'libcalendaring.trigger' . $r . $val[1];
+                $text .= ' ' . intval($val[0]) . ' ' . $rcube->gettext($label);
+            }
         }
         else {
             return false;
         }
 
         return $text;
     }
 
     /**
      * Get the next alarm (time & action) for the given event
      *
      * @param array Record data
      * @return array Hash array with alarm time/type or null if no alarms are configured
      */
     public static function get_next_alarm($rec, $type = 'event')
     {
         if (!($rec['valarms'] || $rec['alarms']) || $rec['cancelled'] || $rec['status'] == 'CANCELLED')
             return null;
 
         if ($type == 'task') {
             $timezone = self::get_instance()->timezone;
             if ($rec['startdate'])
                 $rec['start'] = new DateTime($rec['startdate'] . ' ' . ($rec['starttime'] ?: '12:00'), $timezone);
             if ($rec['date'])
                 $rec[($rec['start'] ? 'end' : 'start')] = new DateTime($rec['date'] . ' ' . ($rec['time'] ?: '12:00'), $timezone);
         }
 
         if (!$rec['end'])
             $rec['end'] = $rec['start'];
 
         // support legacy format
         if (!$rec['valarms']) {
             list($trigger, $action) = explode(':', $rec['alarms'], 2);
             if ($alarm = self::parse_alarm_value($trigger)) {
                 $rec['valarms'] = array(array('action' => $action, 'trigger' => $alarm[3] ?: $alarm[0]));
             }
         }
 
-        $expires = new DateTime('now - 12 hours');
+        $expires  = new DateTime('now - 12 hours');
         $alarm_id = $rec['id'];  // alarm ID eq. record ID by default to keep backwards compatibility
 
         // handle multiple alarms
         $notify_at = null;
         foreach ($rec['valarms'] as $alarm) {
             $notify_time = null;
 
             if ($alarm['trigger'] instanceof DateTime) {
                 $notify_time = $alarm['trigger'];
             }
             else if (is_string($alarm['trigger'])) {
-//                $refdate = $alarm['trigger'][0] == '+' ? $rec['end'] : $rec['start'];
-                $refdate = $rec['start'];
+                $refdate = $alarm['related'] == 'END' ? $rec['end'] : $rec['start'];
 
                 // abort if no reference date is available to compute notification time
                 if (!is_a($refdate, 'DateTime'))
                     continue;
 
                 // TODO: for all-day events, take start @ 00:00 as reference date ?
 
                 try {
                     $interval = new DateInterval(trim($alarm['trigger'], '+-'));
-                    $interval->invert = $alarm['trigger'][0] != '+';
+                    $interval->invert = $alarm['trigger'][0] == '-';
                     $notify_time = clone $refdate;
                     $notify_time->add($interval);
                 }
                 catch (Exception $e) {
                     rcube::raise_error($e, true);
                     continue;
                 }
             }
 
             if ($notify_time && (!$notify_at || ($notify_time > $notify_at && $notify_time > $expires))) {
                 $notify_at  = $notify_time;
                 $action     = $alarm['action'];
                 $alarm_prop = $alarm;
 
                 // generate a unique alarm ID if multiple alarms are set
                 if (count($rec['valarms']) > 1) {
                     $alarm_id = substr(md5($rec['id']), 0, 16) . '-' . $notify_at->format('Ymd\THis');
                 }
             }
         }
 
         return !$notify_at ? null : array(
             'time'   => $notify_at->format('U'),
             'action' => $action ? strtoupper($action) : 'DISPLAY',
             'id'     => $alarm_id,
             'prop'   => $alarm_prop,
         );
     }
 
     /**
      * Handler for keep-alive requests
      * This will check for pending notifications and pass them to the client
      */
     public function refresh($attr)
     {
         // collect pending alarms from all providers (e.g. calendar, tasks)
         $plugin = $this->rc->plugins->exec_hook('pending_alarms', array(
             'time' => time(),
             'alarms' => array(),
         ));
 
         if (!$plugin['abort'] && !empty($plugin['alarms'])) {
             // make sure texts and env vars are available on client
             $this->add_texts('localization/', true);
             $this->rc->output->add_label('close');
             $this->rc->output->set_env('snooze_select', $this->snooze_select());
             $this->rc->output->command('plugin.display_alarms', $this->_alarms_output($plugin['alarms']));
         }
     }
 
     /**
      * Handler for alarm dismiss/snooze requests
      */
     public function alarms_action()
     {
 //        $action = rcube_utils::get_input_value('action', rcube_utils::INPUT_GPC);
         $data  = rcube_utils::get_input_value('data', rcube_utils::INPUT_POST, true);
 
         $data['ids'] = explode(',', $data['id']);
         $plugin = $this->rc->plugins->exec_hook('dismiss_alarms', $data);
 
         if ($plugin['success'])
             $this->rc->output->show_message('successfullysaved', 'confirmation');
         else
             $this->rc->output->show_message('calendar.errorsaving', 'error');
     }
 
     /**
      * Generate reduced and streamlined output for pending alarms
      */
     private function _alarms_output($alarms)
     {
         $out = array();
         foreach ($alarms as $alarm) {
             $out[] = array(
                 'id'       => $alarm['id'],
                 'start'    => $alarm['start'] ? $this->adjust_timezone($alarm['start'])->format('c') : '',
                 'end'      => $alarm['end']   ? $this->adjust_timezone($alarm['end'])->format('c') : '',
                 'allDay'   => ($alarm['allday'] == 1)?true:false,
                 'title'    => $alarm['title'],
                 'location' => $alarm['location'],
                 'calendar' => $alarm['calendar'],
             );
         }
 
         return $out;
     }
 
     /**
      * Render a dropdown menu to choose snooze time
      */
     private function snooze_select($attrib = array())
     {
         $steps = array(
              5 => 'repeatinmin',
             10 => 'repeatinmin',
             15 => 'repeatinmin',
             20 => 'repeatinmin',
             30 => 'repeatinmin',
             60 => 'repeatinhr',
             120 => 'repeatinhrs',
             1440 => 'repeattomorrow',
             10080 => 'repeatinweek',
         );
 
         $items = array();
         foreach ($steps as $n => $label) {
             $items[] = html::tag('li', null, html::a(array('href' => "#" . ($n * 60), 'class' => 'active'),
                 $this->gettext(array('name' => $label, 'vars' => array('min' => $n % 60, 'hrs' => intval($n / 60))))));
         }
 
         return html::tag('ul', $attrib + array('class' => 'toolbarmenu'), join("\n", $items), html::$common_attrib);
     }
 
 
     /*********  Recurrence rules handling ********/
 
     /**
      * Render localized text describing the recurrence rule of an event
      */
     public function recurrence_text($rrule)
     {
         // derive missing FREQ and INTERVAL from RDATE list
         if (empty($rrule['FREQ']) && !empty($rrule['RDATE'])) {
             $first = $rrule['RDATE'][0];
             $second = $rrule['RDATE'][1];
             $third  = $rrule['RDATE'][2];
             if (is_a($first, 'DateTime') && is_a($second, 'DateTime')) {
                 $diff = $first->diff($second);
                 foreach (array('y' => 'YEARLY', 'm' => 'MONTHLY', 'd' => 'DAILY') as $k => $freq) {
                     if ($diff->$k != 0) {
                         $rrule['FREQ'] = $freq;
                         $rrule['INTERVAL'] = $diff->$k;
 
                         // verify interval with next item
                         if (is_a($third, 'DateTime')) {
                             $diff2 = $second->diff($third);
                             if ($diff2->$k != $diff->$k) {
                                 unset($rrule['INTERVAL']);
                             }
                         }
                         break;
                     }
                 }
             }
             if (!$rrule['INTERVAL']) {
                 $rrule['FREQ'] = 'RDATE';
             }
             $rrule['UNTIL'] = end($rrule['RDATE']);
         }
 
         $freq = sprintf('%s %d ', $this->gettext('every'), $rrule['INTERVAL']);
         $details = '';
         switch ($rrule['FREQ']) {
             case 'DAILY':
                 $freq .= $this->gettext('days');
                 break;
             case 'WEEKLY':
                 $freq .= $this->gettext('weeks');
                 break;
             case 'MONTHLY':
                 $freq .= $this->gettext('months');
                 break;
             case 'YEARLY':
                 $freq .= $this->gettext('years');
                 break;
         }
 
         if ($rrule['INTERVAL'] <= 1) {
             $freq = $this->gettext(strtolower($rrule['FREQ']));
         }
 
         if ($rrule['COUNT']) {
             $until =  $this->gettext(array('name' => 'forntimes', 'vars' => array('nr' => $rrule['COUNT'])));
         }
         else if ($rrule['UNTIL']) {
             $until = $this->gettext('recurrencend') . ' ' . format_date($rrule['UNTIL'], self::to_php_date_format($this->rc->config->get('calendar_date_format', $this->defaults['calendar_date_format'])));
         }
         else {
             $until = $this->gettext('forever');
         }
 
         $except = '';
         if (is_array($rrule['EXDATE']) && !empty($rrule['EXDATE'])) {
           $format = self::to_php_date_format($this->rc->config->get('calendar_date_format', $this->defaults['calendar_date_format']));
           $exdates = array_map(
             function($dt) use ($format) { return format_date($dt, $format); },
             array_slice($rrule['EXDATE'], 0, 10)
           );
           $except = '; ' . $this->gettext('except') . ' ' . join(', ', $exdates);
         }
 
         return rtrim($freq . $details . ', ' . $until . $except);
     }
 
     /**
      * Generate the form for recurrence settings
      */
     public function recurrence_form($attrib = array())
     {
         switch ($attrib['part']) {
             // frequency selector
             case 'frequency':
                 $select = new html_select(array('name' => 'frequency', 'id' => 'edit-recurrence-frequency'));
                 $select->add($this->gettext('never'),   '');
                 $select->add($this->gettext('daily'),   'DAILY');
                 $select->add($this->gettext('weekly'),  'WEEKLY');
                 $select->add($this->gettext('monthly'), 'MONTHLY');
                 $select->add($this->gettext('yearly'),  'YEARLY');
                 $select->add($this->gettext('rdate'),   'RDATE');
                 $html = html::label('edit-recurrence-frequency', $this->gettext('frequency')) . $select->show('');
                 break;
 
             // daily recurrence
             case 'daily':
                 $select = $this->interval_selector(array('name' => 'interval', 'class' => 'edit-recurrence-interval', 'id' => 'edit-recurrence-interval-daily'));
                 $html = html::div($attrib, html::label('edit-recurrence-interval-daily', $this->gettext('every')) . $select->show(1) . html::span('label-after', $this->gettext('days')));
                 break;
 
             // weekly recurrence form
             case 'weekly':
                 $select = $this->interval_selector(array('name' => 'interval', 'class' => 'edit-recurrence-interval', 'id' => 'edit-recurrence-interval-weekly'));
                 $html = html::div($attrib, html::label('edit-recurrence-interval-weekly', $this->gettext('every')) . $select->show(1) . html::span('label-after', $this->gettext('weeks')));
                 // weekday selection
                 $daymap = array('sun','mon','tue','wed','thu','fri','sat');
                 $checkbox = new html_checkbox(array('name' => 'byday', 'class' => 'edit-recurrence-weekly-byday'));
                 $first = $this->rc->config->get('calendar_first_day', 1);
                 for ($weekdays = '', $j = $first; $j <= $first+6; $j++) {
                     $d = $j % 7;
                     $weekdays .= html::label(array('class' => 'weekday'),
                         $checkbox->show('', array('value' => strtoupper(substr($daymap[$d], 0, 2)))) .
                         $this->gettext($daymap[$d])
                     ) . ' ';
                 }
                 $html .= html::div($attrib, html::label(null, $this->gettext('bydays')) . $weekdays);
                 break;
 
             // monthly recurrence form
             case 'monthly':
                 $select = $this->interval_selector(array('name' => 'interval', 'class' => 'edit-recurrence-interval', 'id' => 'edit-recurrence-interval-monthly'));
                 $html = html::div($attrib, html::label('edit-recurrence-interval-monthly', $this->gettext('every')) . $select->show(1) . html::span('label-after', $this->gettext('months')));
 
                 $checkbox = new html_checkbox(array('name' => 'bymonthday', 'class' => 'edit-recurrence-monthly-bymonthday'));
                 for ($monthdays = '', $d = 1; $d <= 31; $d++) {
                     $monthdays .= html::label(array('class' => 'monthday'), $checkbox->show('', array('value' => $d)) . $d);
                     $monthdays .= $d % 7 ? ' ' : html::br();
                 }
 
                 // rule selectors
                 $radio = new html_radiobutton(array('name' => 'repeatmode', 'class' => 'edit-recurrence-monthly-mode'));
                 $table = new html_table(array('cols' => 2, 'border' => 0, 'cellpadding' => 0, 'class' => 'formtable'));
                 $table->add('label', html::label(null, $radio->show('BYMONTHDAY', array('value' => 'BYMONTHDAY')) . ' ' . $this->gettext('each')));
                 $table->add(null, $monthdays);
                 $table->add('label', html::label(null, $radio->show('', array('value' => 'BYDAY')) . ' ' . $this->gettext('onevery')));
                 $table->add(null, $this->rrule_selectors($attrib['part']));
 
                 $html .= html::div($attrib, $table->show());
                 break;
 
             // annually recurrence form
             case 'yearly':
                 $select = $this->interval_selector(array('name' => 'interval', 'class' => 'edit-recurrence-interval', 'id' => 'edit-recurrence-interval-yearly'));
                 $html = html::div($attrib, html::label('edit-recurrence-interval-yearly', $this->gettext('every')) . $select->show(1) . html::span('label-after', $this->gettext('years')));
                 // month selector
                 $monthmap = array('','jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec');
                 $checkbox = new html_checkbox(array('name' => 'bymonth', 'class' => 'edit-recurrence-yearly-bymonth'));
                 for ($months = '', $m = 1; $m <= 12; $m++) {
                     $months .= html::label(array('class' => 'month'), $checkbox->show(null, array('value' => $m)) . $this->gettext($monthmap[$m]));
                     $months .= $m % 4 ? ' ' : html::br();
                 }
                 $html .= html::div($attrib + array('id' => 'edit-recurrence-yearly-bymonthblock'), $months);
 
                 // day rule selection
                 $html .= html::div($attrib, html::label(null, $this->gettext('onevery')) . $this->rrule_selectors($attrib['part'], '---'));
                 break;
 
             // end of recurrence form
             case 'until':
                 $radio = new html_radiobutton(array('name' => 'repeat', 'class' => 'edit-recurrence-until'));
                 $select = $this->interval_selector(array('name' => 'times', 'id' => 'edit-recurrence-repeat-times'));
                 $input = new html_inputfield(array('name' => 'untildate', 'id' => 'edit-recurrence-enddate', 'size' => "10"));
 
                 $html = html::div('line first',
                     html::label(null, $radio->show('', array('value' => '', 'id' => 'edit-recurrence-repeat-forever')) . ' ' .
                         $this->gettext('forever'))
                 );
 
                 $forntimes = $this->gettext(array(
                     'name' => 'forntimes',
                     'vars' => array('nr' => '%s'))
                 );
                 $html .= html::div('line',
                     $radio->show('', array('value' => 'count', 'id' => 'edit-recurrence-repeat-count', 'aria-label' => sprintf($forntimes, 'N'))) . ' ' .
                         sprintf($forntimes, $select->show(1))
                 );
 
                 $html .= html::div('line',
                     $radio->show('', array('value' => 'until', 'id' => 'edit-recurrence-repeat-until', 'aria-label' => $this->gettext('untilenddate'))) . ' ' .
                         $this->gettext('untildate') . ' ' . $input->show('', array('aria-label' => $this->gettext('untilenddate')))
                 );
 
                 $html = html::div($attrib, html::label(null, ucfirst($this->gettext('recurrencend'))) . $html);
                 break;
 
             case 'rdate':
                 $ul = html::tag('ul', array('id' => 'edit-recurrence-rdates'), '');
                 $input = new html_inputfield(array('name' => 'rdate', 'id' => 'edit-recurrence-rdate-input', 'size' => "10"));
                 $button = new html_inputfield(array('type' => 'button', 'class' => 'button add', 'value' => $this->gettext('addrdate')));
                 $html .= html::div($attrib, $ul . html::div('inputform', $input->show() . $button->show()));
                 break;
         }
 
         return $html;
     }
 
     /**
      * Input field for interval selection
      */
     private function interval_selector($attrib)
     {
         $select = new html_select($attrib);
         $select->add(range(1,30), range(1,30));
         return $select;
     }
 
     /**
      * Drop-down menus for recurrence rules like "each last sunday of"
      */
     private function rrule_selectors($part, $noselect = null)
     {
         // rule selectors
         $select_prefix = new html_select(array('name' => 'bydayprefix', 'id' => "edit-recurrence-$part-prefix"));
         if ($noselect) $select_prefix->add($noselect, '');
         $select_prefix->add(array(
                 $this->gettext('first'),
                 $this->gettext('second'),
                 $this->gettext('third'),
                 $this->gettext('fourth'),
                 $this->gettext('last')
             ),
             array(1, 2, 3, 4, -1));
 
         $select_wday = new html_select(array('name' => 'byday', 'id' => "edit-recurrence-$part-byday"));
         if ($noselect) $select_wday->add($noselect, '');
 
         $daymap = array('sunday','monday','tuesday','wednesday','thursday','friday','saturday');
         $first = $this->rc->config->get('calendar_first_day', 1);
         for ($j = $first; $j <= $first+6; $j++) {
             $d = $j % 7;
             $select_wday->add($this->gettext($daymap[$d]), strtoupper(substr($daymap[$d], 0, 2)));
         }
 
         return $select_prefix->show() . '&nbsp;' . $select_wday->show();
     }
 
     /**
      * Convert the recurrence settings to be processed on the client
      */
     public function to_client_recurrence($recurrence, $allday = false)
     {
         if ($recurrence['UNTIL'])
             $recurrence['UNTIL'] = $this->adjust_timezone($recurrence['UNTIL'], $allday)->format('c');
 
         // format RDATE values
         if (is_array($recurrence['RDATE'])) {
             $libcal = $this;
             $recurrence['RDATE'] = array_map(function($rdate) use ($libcal) {
                 return $libcal->adjust_timezone($rdate, true)->format('c');
             }, $recurrence['RDATE']);
         }
 
         unset($recurrence['EXCEPTIONS']);
 
         return $recurrence;
     }
 
     /**
      * Process the alarms values submitted by the client
      */
     public function from_client_recurrence($recurrence, $start = null)
     {
         if (is_array($recurrence) && !empty($recurrence['UNTIL'])) {
             $recurrence['UNTIL'] = new DateTime($recurrence['UNTIL'], $this->timezone);
         }
 
         if (is_array($recurrence) && is_array($recurrence['RDATE'])) {
             $tz = $this->timezone;
             $recurrence['RDATE'] = array_map(function($rdate) use ($tz, $start) {
                 try {
                     $dt = new DateTime($rdate, $tz);
                     if (is_a($start, 'DateTime'))
                         $dt->setTime($start->format('G'), $start->format('i'));
                     return $dt;
                 }
                 catch (Exception $e) {
                     return null;
                 }
             }, $recurrence['RDATE']);
         }
 
         return $recurrence;
     }
 
 
     /*********  Attachments handling  *********/
 
     /**
      * Handler for attachment uploads
      */
     public function attachment_upload($session_key, $id_prefix = '')
     {
         // Upload progress update
         if (!empty($_GET['_progress'])) {
             $this->rc->upload_progress();
         }
 
         $recid = $id_prefix . rcube_utils::get_input_value('_id', rcube_utils::INPUT_GPC);
         $uploadid = rcube_utils::get_input_value('_uploadid', rcube_utils::INPUT_GPC);
 
         if (!is_array($_SESSION[$session_key]) || $_SESSION[$session_key]['id'] != $recid) {
             $_SESSION[$session_key] = array();
             $_SESSION[$session_key]['id'] = $recid;
             $_SESSION[$session_key]['attachments'] = array();
         }
 
         // clear all stored output properties (like scripts and env vars)
         $this->rc->output->reset();
 
         if (is_array($_FILES['_attachments']['tmp_name'])) {
             foreach ($_FILES['_attachments']['tmp_name'] as $i => $filepath) {
               // Process uploaded attachment if there is no error
               $err = $_FILES['_attachments']['error'][$i];
 
               if (!$err) {
                 $attachment = array(
                     'path' => $filepath,
                     'size' => $_FILES['_attachments']['size'][$i],
                     'name' => $_FILES['_attachments']['name'][$i],
                     'mimetype' => rcube_mime::file_content_type($filepath, $_FILES['_attachments']['name'][$i], $_FILES['_attachments']['type'][$i]),
                     'group' => $recid,
                 );
 
                 $attachment = $this->rc->plugins->exec_hook('attachment_upload', $attachment);
               }
 
               if (!$err && $attachment['status'] && !$attachment['abort']) {
                   $id = $attachment['id'];
 
                   // store new attachment in session
                   unset($attachment['status'], $attachment['abort']);
                   $_SESSION[$session_key]['attachments'][$id] = $attachment;
 
                   if (($icon = $_SESSION[$session_key . '_deleteicon']) && is_file($icon)) {
                       $button = html::img(array(
                           'src' => $icon,
                           'alt' => $this->rc->gettext('delete')
                       ));
                   }
                   else {
                       $button = Q($this->rc->gettext('delete'));
                   }
 
                   $content = html::a(array(
                       'href' => "#delete",
                       'class' => 'delete',
                       'onclick' => sprintf("return %s.remove_from_attachment_list('rcmfile%s')", JS_OBJECT_NAME, $id),
                       'title' => $this->rc->gettext('delete'),
                       'aria-label' => $this->rc->gettext('delete') . ' ' . $attachment['name'],
                   ), $button);
 
                   $content .= Q($attachment['name']);
 
                   $this->rc->output->command('add2attachment_list', "rcmfile$id", array(
                       'html' => $content,
                       'name' => $attachment['name'],
                       'mimetype' => $attachment['mimetype'],
                       'classname' => rcube_utils::file2class($attachment['mimetype'], $attachment['name']),
                       'complete' => true), $uploadid);
               }
               else {  // upload failed
                   if ($err == UPLOAD_ERR_INI_SIZE || $err == UPLOAD_ERR_FORM_SIZE) {
                     $msg = $this->rc->gettext(array('name' => 'filesizeerror', 'vars' => array(
                         'size' => show_bytes(parse_bytes(ini_get('upload_max_filesize'))))));
                   }
                   else if ($attachment['error']) {
                       $msg = $attachment['error'];
                   }
                   else {
                       $msg = $this->rc->gettext('fileuploaderror');
                   }
 
                   $this->rc->output->command('display_message', $msg, 'error');
                   $this->rc->output->command('remove_from_attachment_list', $uploadid);
                 }
             }
         }
         else if ($_SERVER['REQUEST_METHOD'] == 'POST') {
             // if filesize exceeds post_max_size then $_FILES array is empty,
             // show filesizeerror instead of fileuploaderror
             if ($maxsize = ini_get('post_max_size'))
                 $msg = $this->rc->gettext(array('name' => 'filesizeerror', 'vars' => array(
                     'size' => show_bytes(parse_bytes($maxsize)))));
             else
                 $msg = $this->rc->gettext('fileuploaderror');
 
             $this->rc->output->command('display_message', $msg, 'error');
             $this->rc->output->command('remove_from_attachment_list', $uploadid);
         }
 
         $this->rc->output->send('iframe');
     }
 
 
     /**
      * Deliver an event/task attachment to the client
      * (similar as in Roundcube core program/steps/mail/get.inc)
      */
     public function attachment_get($attachment)
     {
         ob_end_clean();
 
         if ($attachment && $attachment['body']) {
             // allow post-processing of the attachment body
             $part = new rcube_message_part;
             $part->filename  = $attachment['name'];
             $part->size      = $attachment['size'];
             $part->mimetype  = $attachment['mimetype'];
 
             $plugin = $this->rc->plugins->exec_hook('message_part_get', array(
                 'body'     => $attachment['body'],
                 'mimetype' => strtolower($attachment['mimetype']),
                 'download' => !empty($_GET['_download']),
                 'part'     => $part,
             ));
 
             if ($plugin['abort'])
                 exit;
 
             $mimetype = $plugin['mimetype'];
             list($ctype_primary, $ctype_secondary) = explode('/', $mimetype);
 
             $browser = $this->rc->output->browser;
 
             // send download headers
             if ($plugin['download']) {
                 header("Content-Type: application/octet-stream");
                 if ($browser->ie)
                     header("Content-Type: application/force-download");
             }
             else if ($ctype_primary == 'text') {
                 header("Content-Type: text/$ctype_secondary");
             }
             else {
                 header("Content-Type: $mimetype");
                 header("Content-Transfer-Encoding: binary");
             }
 
             // display page, @TODO: support text/plain (and maybe some other text formats)
             if ($mimetype == 'text/html' && empty($_GET['_download'])) {
                 $OUTPUT = new rcube_html_page();
                 // @TODO: use washtml on $body
                 $OUTPUT->write($plugin['body']);
             }
             else {
                 // don't kill the connection if download takes more than 30 sec.
                 @set_time_limit(0);
 
                 $filename = $attachment['name'];
                 $filename = preg_replace('[\r\n]', '', $filename);
 
                 if ($browser->ie && $browser->ver < 7)
                     $filename = rawurlencode(abbreviate_string($filename, 55));
                 else if ($browser->ie)
                     $filename = rawurlencode($filename);
                 else
                     $filename = addcslashes($filename, '"');
 
                 $disposition = !empty($_GET['_download']) ? 'attachment' : 'inline';
                 header("Content-Disposition: $disposition; filename=\"$filename\"");
 
                 echo $plugin['body'];
             }
 
             exit;
         }
 
         // if we arrive here, the requested part was not found
         header('HTTP/1.1 404 Not Found');
         exit;
     }
 
     /**
      * Show "loading..." page in attachment iframe
      */
     public function attachment_loading_page()
     {
         $url = str_replace('&_preload=1', '', $_SERVER['REQUEST_URI']);
         $message = $this->rc->gettext('loadingdata');
 
         header('Content-Type: text/html; charset=' . RCUBE_CHARSET);
         print "<html>\n<head>\n"
             . '<meta http-equiv="refresh" content="0; url='.Q($url).'">' . "\n"
             . '<meta http-equiv="content-type" content="text/html; charset='.RCUBE_CHARSET.'">' . "\n"
             . "</head>\n<body>\n$message\n</body>\n</html>";
         exit;
     }
 
     /**
      * Template object for attachment display frame
      */
     public function attachment_frame($attrib = array())
     {
         $mimetype = strtolower($this->attachment['mimetype']);
         list($ctype_primary, $ctype_secondary) = explode('/', $mimetype);
 
         $attrib['src'] = './?' . str_replace('_frame=', ($ctype_primary == 'text' ? '_show=' : '_preload='), $_SERVER['QUERY_STRING']);
 
         $this->rc->output->add_gui_object('attachmentframe', $attrib['id']);
 
         return html::iframe($attrib);
     }
 
     /**
      *
      */
     public function attachment_header($attrib = array())
     {
         $rcmail = rcmail::get_instance();
         $dl_link = strtolower($attrib['downloadlink']) == 'true';
         $dl_url = $this->rc->url(array('_frame' => null, '_download' => 1) + $_GET);
 
         $table = new html_table(array('cols' => $dl_link ? 3 : 2));
 
         if (!empty($this->attachment['name'])) {
             $table->add('title', Q($this->rc->gettext('filename')));
             $table->add('header', Q($this->attachment['name']));
             if ($dl_link) {
                 $table->add('download-link', html::a($dl_url, Q($this->rc->gettext('download'))));
             }
         }
 
         if (!empty($this->attachment['mimetype'])) {
             $table->add('title', Q($this->rc->gettext('type')));
             $table->add('header', Q($this->attachment['mimetype']));
         }
 
         if (!empty($this->attachment['size'])) {
             $table->add('title', Q($this->rc->gettext('filesize')));
             $table->add('header', Q(show_bytes($this->attachment['size'])));
         }
 
         $this->rc->output->set_env('attachment_download_url', $dl_url);
 
         return $table->show($attrib);
     }
 
 
     /*********  iTip message detection  *********/
 
     /**
      * Check mail message structure of there are .ics files attached
      */
     public function mail_message_load($p)
     {
         $this->ical_message = $p['object'];
         $itip_part     = null;
 
         // check all message parts for .ics files
         foreach ((array)$this->ical_message->mime_parts as $part) {
             if (self::part_is_vcalendar($part)) {
                 if ($part->ctype_parameters['method'])
                     $itip_part = $part->mime_id;
                 else
                     $this->ical_parts[] = $part->mime_id;
             }
         }
 
         // priorize part with method parameter
         if ($itip_part) {
             $this->ical_parts = array($itip_part);
         }
     }
 
     /**
      * Getter for the parsed iCal objects attached to the current email message
      *
      * @return object libvcalendar parser instance with the parsed objects
      */
     public function get_mail_ical_objects()
     {
         // create parser and load ical objects
         if (!$this->mail_ical_parser) {
             $this->mail_ical_parser = $this->get_ical();
 
             foreach ($this->ical_parts as $mime_id) {
                 $part    = $this->ical_message->mime_parts[$mime_id];
                 $charset = $part->ctype_parameters['charset'] ?: RCMAIL_CHARSET;
                 $this->mail_ical_parser->import($this->ical_message->get_part_body($mime_id, true), $charset);
 
                 // check if the parsed object is an instance of a recurring event/task
                 array_walk($this->mail_ical_parser->objects, 'libcalendaring::identify_recurrence_instance');
 
                 // stop on the part that has an iTip method specified
                 if (count($this->mail_ical_parser->objects) && $this->mail_ical_parser->method) {
                     $this->mail_ical_parser->message_date = $this->ical_message->headers->date;
                     $this->mail_ical_parser->mime_id = $mime_id;
 
                     // store the message's sender address for comparisons
                     $this->mail_ical_parser->sender = preg_match(self::$email_regex, $this->ical_message->headers->from, $m) ? $m[1] : '';
                     if (!empty($this->mail_ical_parser->sender)) {
                         foreach ($this->mail_ical_parser->objects as $i => $object) {
                             $this->mail_ical_parser->objects[$i]['_sender'] = $this->mail_ical_parser->sender;
                             $this->mail_ical_parser->objects[$i]['_sender_utf'] = rcube_utils::idn_to_utf8($this->mail_ical_parser->sender);
                         }
                     }
                     break;
                 }
             }
         }
 
         return $this->mail_ical_parser;
     }
 
     /**
      * Read the given mime message from IMAP and parse ical data
      *
      * @param string Mailbox name
      * @param string Message UID
      * @param string Message part ID and object index (e.g. '1.2:0')
      * @param string Object type filter (optional)
      *
      * @return array Hash array with the parsed iCal 
      */
     public function mail_get_itip_object($mbox, $uid, $mime_id, $type = null)
     {
         $charset = RCMAIL_CHARSET;
 
         // establish imap connection
         $imap = $this->rc->get_storage();
         $imap->set_mailbox($mbox);
 
         if ($uid && $mime_id) {
             list($mime_id, $index) = explode(':', $mime_id);
 
             $part    = $imap->get_message_part($uid, $mime_id);
             $headers = $imap->get_message_headers($uid);
             $parser  = $this->get_ical();
 
             if ($part->ctype_parameters['charset']) {
                 $charset = $part->ctype_parameters['charset'];
             }
 
             if ($part) {
                 $objects = $parser->import($part, $charset);
             }
         }
 
         // successfully parsed events/tasks?
         if (!empty($objects) && ($object = $objects[$index]) && (!$type || $object['_type'] == $type)) {
             if ($parser->method)
                 $object['_method'] = $parser->method;
 
             // store the message's sender address for comparisons
             $object['_sender'] = preg_match(self::$email_regex, $headers->from, $m) ? $m[1] : '';
             $object['_sender_utf'] = rcube_utils::idn_to_utf8($object['_sender']);
 
             // check if this is an instance of a recurring event/task
             self::identify_recurrence_instance($object);
 
             return $object;
         }
 
         return null;
     }
 
     /**
      * Checks if specified message part is a vcalendar data
      *
      * @param rcube_message_part Part object
      * @return boolean True if part is of type vcard
      */
     public static function part_is_vcalendar($part)
     {
         return (
             in_array($part->mimetype, array('text/calendar', 'text/x-vcalendar', 'application/ics')) ||
             // Apple sends files as application/x-any (!?)
             ($part->mimetype == 'application/x-any' && $part->filename && preg_match('/\.ics$/i', $part->filename))
         );
     }
 
     /**
      * Single occourrences of recurring events are identified by their RECURRENCE-ID property
      * in iCal which is represented as 'recurrence_date' in our internal data structure.
      *
      * Check if such a property exists and derive the '_instance' identifier and '_savemode'
      * attributes which are used in the storage backend to identify the nested exception item.
      */
     public static function identify_recurrence_instance(&$object)
     {
         // for savemode=all, remove recurrence instance identifiers
         if (!empty($object['_savemode']) && $object['_savemode'] == 'all' && $object['recurrence']) {
             unset($object['_instance'], $object['recurrence_date']);
         }
         // set instance and 'savemode' according to recurrence-id
         else if (!empty($object['recurrence_date']) && is_a($object['recurrence_date'], 'DateTime')) {
             $object['_instance'] = self::recurrence_instance_identifier($object);
             $object['_savemode'] = $object['thisandfuture'] ? 'future' : 'current';
         }
         else if (!empty($object['recurrence_id']) && !empty($object['_instance'])) {
             if (strlen($object['_instance']) > 4) {
                 $object['recurrence_date'] = rcube_utils::anytodatetime($object['_instance'], $object['start']->getTimezone());
             }
             else {
                 $object['recurrence_date'] = clone $object['start'];
             }
         }
     }
 
     /**
      * Return a date() format string to render identifiers for recurrence instances
      *
      * @param array Hash array with event properties
      * @return string Format string
      */
     public static function recurrence_id_format($event)
     {
         return $event['allday'] ? 'Ymd' : 'Ymd\THis';
     }
 
     /**
      * Return the identifer for the given instance of a recurring event
      *
      * @param array Hash array with event properties
      * @return mixed Format string or null if identifier cannot be generated
      */
     public static function recurrence_instance_identifier($event)
     {
         $instance_date = $event['recurrence_date'] ?: $event['start'];
 
         if ($instance_date && is_a($instance_date, 'DateTime')) {
           $recurrence_id_format = $event['allday'] ? 'Ymd' : 'Ymd\THis';
           return $instance_date->format($recurrence_id_format);
         }
 
         return null;
     }
 
 
     /*********  Attendee handling functions  *********/
 
     /**
      * Handler for attendee group expansion requests
      */
     public function expand_attendee_group()
     {
         $id     = rcube_utils::get_input_value('id', rcube_utils::INPUT_POST);
         $data   = rcube_utils::get_input_value('data', rcube_utils::INPUT_POST, true);
         $result = array('id' => $id, 'members' => array());
         $maxnum = 500;
 
         // iterate over all autocomplete address books (we don't know the source of the group)
         foreach ((array)$this->rc->config->get('autocomplete_addressbooks', 'sql') as $abook_id) {
             if (($abook = $this->rc->get_address_book($abook_id)) && $abook->groups) {
                 foreach ($abook->list_groups($data['name'], 1) as $group) {
                     // this is the matching group to expand
                     if (in_array($data['email'], (array)$group['email'])) {
                         $abook->set_pagesize($maxnum);
                         $abook->set_group($group['ID']);
 
                         // get all members
                         $res = $abook->list_records($this->rc->config->get('contactlist_fields'));
 
                         // handle errors (e.g. sizelimit, timelimit)
                         if ($abook->get_error()) {
                             $result['error'] = $this->rc->gettext('expandattendeegrouperror', 'libcalendaring');
                             $res = false;
                         }
                         // check for maximum number of members (we don't wanna bloat the UI too much)
                         else if ($res->count > $maxnum) {
                             $result['error'] = $this->rc->gettext('expandattendeegroupsizelimit', 'libcalendaring');
                             $res = false;
                         }
 
                         while ($res && ($member = $res->iterate())) {
                             $emails = (array)$abook->get_col_values('email', $member, true);
                             if (!empty($emails) && ($email = array_shift($emails))) {
                                 $result['members'][] = array(
                                     'email' => $email,
                                     'name' => rcube_addressbook::compose_list_name($member),
                                 );
                             }
                         }
 
                         break 2;
                     }
                 }
             }
         }
 
         $this->rc->output->command('plugin.expand_attendee_callback', $result);
     }
 
 
     /*********  Static utility functions  *********/
 
     /**
      * Convert the internal structured data into a vcalendar rrule 2.0 string
      */
     public static function to_rrule($recurrence, $allday = false)
     {
         if (is_string($recurrence))
             return $recurrence;
 
         $rrule = '';
         foreach ((array)$recurrence as $k => $val) {
             $k = strtoupper($k);
             switch ($k) {
             case 'UNTIL':
                 // convert to UTC according to RFC 5545
                 if (is_a($val, 'DateTime')) {
                     if (!$allday && !$val->_dateonly) {
                         $until = clone $val;
                         $until->setTimezone(new DateTimeZone('UTC'));
                         $val = $until->format('Ymd\THis\Z');
                     }
                     else {
                         $val = $val->format('Ymd');
                     }
                 }
                 break;
             case 'RDATE':
             case 'EXDATE':
                 foreach ((array)$val as $i => $ex) {
                     if (is_a($ex, 'DateTime'))
                         $val[$i] = $ex->format('Ymd\THis');
                 }
                 $val = join(',', (array)$val);
                 break;
             case 'EXCEPTIONS':
                 continue 2;
             }
 
             if (strlen($val))
                 $rrule .= $k . '=' . $val . ';';
         }
 
         return rtrim($rrule, ';');
     }
 
     /**
      * Convert from fullcalendar date format to PHP date() format string
      */
     public static function to_php_date_format($from)
     {
         // "dd.MM.yyyy HH:mm:ss" => "d.m.Y H:i:s"
         return strtr(strtr($from, array(
             'yyyy' => 'Y',
             'yy'   => 'y',
             'MMMM' => 'F',
             'MMM'  => 'M',
             'MM'   => 'm',
             'M'    => 'n',
             'dddd' => 'l',
             'ddd'  => 'D',
             'dd'   => 'd',
             'd'    => 'j',
             'HH'   => '**',
             'hh'   => '%%',
             'H'    => 'G',
             'h'    => 'g',
             'mm'   => 'i',
             'ss'   => 's',
             'TT'   => 'A',
             'tt'   => 'a',
             'T'    => 'A',
             't'    => 'a',
             'u'    => 'c',
         )), array(
             '**'   => 'H',
             '%%'   => 'h',
         ));
     }
 
     /**
      * Convert from PHP date() format to fullcalendar format string
      */
     public static function from_php_date_format($from)
     {
         // "d.m.Y H:i:s" => "dd.MM.yyyy HH:mm:ss"
         return strtr($from, array(
             'y' => 'yy',
             'Y' => 'yyyy',
             'M' => 'MMM',
             'F' => 'MMMM',
             'm' => 'MM',
             'n' => 'M',
             'j' => 'd',
             'd' => 'dd',
             'D' => 'ddd',
             'l' => 'dddd',
             'H' => 'HH',
             'h' => 'hh',
             'G' => 'H',
             'g' => 'h',
             'i' => 'mm',
             's' => 'ss',
             'A' => 'TT',
             'a' => 'tt',
             'c' => 'u',
         ));
     }
 
 }
diff --git a/plugins/libcalendaring/libvcalendar.php b/plugins/libcalendaring/libvcalendar.php
index 8df7bd9b..7575b537 100644
--- a/plugins/libcalendaring/libvcalendar.php
+++ b/plugins/libcalendaring/libvcalendar.php
@@ -1,1371 +1,1378 @@
 <?php
 
 /**
  * iCalendar functions for the libcalendaring plugin
  *
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2013-2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 use \Sabre\VObject;
 
 // load Sabre\VObject classes
 if (!class_exists('\Sabre\VObject\Reader')) {
     require_once __DIR__ . '/lib/Sabre/VObject/includes.php';
 }
 
 /**
  * Class to parse and build vCalendar (iCalendar) files
  *
  * Uses the SabreTooth VObject library, version 2.1.
  *
  * Download from https://github.com/fruux/sabre-vobject/archive/2.1.0.zip
  * and place the lib files in this plugin's lib directory
  *
  */
 class libvcalendar implements Iterator
 {
     private $timezone;
     private $attach_uri = null;
     private $prodid = '-//Roundcube libcalendaring//Sabre//Sabre VObject//EN';
     private $type_component_map = array('event' => 'VEVENT', 'task' => 'VTODO');
     private $attendee_keymap = array('name' => 'CN', 'status' => 'PARTSTAT', 'role' => 'ROLE',
         'cutype' => 'CUTYPE', 'rsvp' => 'RSVP', 'delegated-from' => 'DELEGATED-FROM', 'delegated-to' => 'DELEGATED-TO');
     private $iteratorkey = 0;
     private $charset;
     private $forward_exceptions;
     private $vhead;
     private $fp;
     private $vtimezones = array();
 
     public $method;
     public $agent = '';
     public $objects = array();
     public $freebusy = array();
 
 
     /**
      * Default constructor
      */
     function __construct($tz = null)
     {
         $this->timezone = $tz;
         $this->prodid = '-//Roundcube libcalendaring ' . RCUBE_VERSION . '//Sabre//Sabre VObject ' . VObject\Version::VERSION . '//EN';
     }
 
     /**
      * Setter for timezone information
      */
     public function set_timezone($tz)
     {
         $this->timezone = $tz;
     }
 
     /**
      * Setter for URI template for attachment links
      */
     public function set_attach_uri($uri)
     {
         $this->attach_uri = $uri;
     }
 
     /**
      * Setter for a custom PRODID attribute
      */
     public function set_prodid($prodid)
     {
         $this->prodid = $prodid;
     }
 
     /**
      * Setter for a user-agent string to tweak input/output accordingly
      */
     public function set_agent($agent)
     {
         $this->agent = $agent;
     }
 
     /**
      * Free resources by clearing member vars
      */
     public function reset()
     {
         $this->vhead = '';
         $this->method = '';
         $this->objects = array();
         $this->freebusy = array();
         $this->vtimezones = array();
         $this->iteratorkey = 0;
 
         if ($this->fp) {
             fclose($this->fp);
             $this->fp = null;
         }
     }
 
     /**
     * Import events from iCalendar format
     *
     * @param  string vCalendar input
     * @param  string Input charset (from envelope)
     * @param  boolean True if parsing exceptions should be forwarded to the caller
     * @return array List of events extracted from the input
     */
     public function import($vcal, $charset = 'UTF-8', $forward_exceptions = false, $memcheck = true)
     {
         // TODO: convert charset to UTF-8 if other
 
         try {
             // estimate the memory usage and try to avoid fatal errors when allowed memory gets exhausted
             if ($memcheck) {
                 $count = substr_count($vcal, 'BEGIN:VEVENT') + substr_count($vcal, 'BEGIN:VTODO');
                 $expected_memory = $count * 70*1024;  // assume ~ 70K per event (empirically determined)
 
                 if (!rcube_utils::mem_check($expected_memory)) {
                     throw new Exception("iCal file too big");
                 }
             }
 
             $vobject = VObject\Reader::read($vcal, VObject\Reader::OPTION_FORGIVING | VObject\Reader::OPTION_IGNORE_INVALID_LINES);
             if ($vobject)
                 return $this->import_from_vobject($vobject);
         }
         catch (Exception $e) {
             if ($forward_exceptions) {
                 throw $e;
             }
             else {
                 rcube::raise_error(array(
                     'code' => 600, 'type' => 'php',
                     'file' => __FILE__, 'line' => __LINE__,
                     'message' => "iCal data parse error: " . $e->getMessage()),
                     true, false);
             }
         }
 
         return array();
     }
 
     /**
     * Read iCalendar events from a file
     *
     * @param  string File path to read from
     * @param  string Input charset (from envelope)
     * @param  boolean True if parsing exceptions should be forwarded to the caller
     * @return array List of events extracted from the file
     */
     public function import_from_file($filepath, $charset = 'UTF-8', $forward_exceptions = false)
     {
         if ($this->fopen($filepath, $charset, $forward_exceptions)) {
             while ($this->_parse_next(false)) {
                 // nop
             }
 
             fclose($this->fp);
             $this->fp = null;
         }
 
         return $this->objects;
     }
 
     /**
      * Open a file to read iCalendar events sequentially
      *
      * @param  string File path to read from
      * @param  string Input charset (from envelope)
      * @param  boolean True if parsing exceptions should be forwarded to the caller
      * @return boolean True if file contents are considered valid
      */
     public function fopen($filepath, $charset = 'UTF-8', $forward_exceptions = false)
     {
         $this->reset();
 
         // just to be sure...
         @ini_set('auto_detect_line_endings', true);
 
         $this->charset = $charset;
         $this->forward_exceptions = $forward_exceptions;
         $this->fp = fopen($filepath, 'r');
 
         // check file content first
         $begin = fread($this->fp, 1024);
         if (!preg_match('/BEGIN:VCALENDAR/i', $begin)) {
             return false;
         }
 
         fseek($this->fp, 0);
         return $this->_parse_next();
     }
 
     /**
      * Parse the next event/todo/freebusy object from the input file
      */
     private function _parse_next($reset = true)
     {
         if ($reset) {
             $this->iteratorkey = 0;
             $this->objects = array();
             $this->freebusy = array();
         }
 
         $next = $this->_next_component();
         $buffer = $next;
 
         // load the next component(s) too, as they could contain recurrence exceptions
         while (preg_match('/(RRULE|RECURRENCE-ID)[:;]/i', $next)) {
             $next = $this->_next_component();
             $buffer .= $next;
         }
 
         // parse the vevent block surrounded with the vcalendar heading
         if (strlen($buffer) && preg_match('/BEGIN:(VEVENT|VTODO|VFREEBUSY)/i', $buffer)) {
             try {
                 $this->import($this->vhead . $buffer . "END:VCALENDAR", $this->charset, true, false);
             }
             catch (Exception $e) {
                 if ($this->forward_exceptions) {
                     throw new VObject\ParseException($e->getMessage() . " in\n" . $buffer);
                 }
                 else {
                     // write the failing section to error log
                     rcube::raise_error(array(
                         'code' => 600, 'type' => 'php',
                         'file' => __FILE__, 'line' => __LINE__,
                         'message' => $e->getMessage() . " in\n" . $buffer),
                         true, false);
                 }
 
                 // advance to next
                 return $this->_parse_next($reset);
             }
 
             return count($this->objects) > 0;
         }
 
         return false;
     }
 
     /**
      * Helper method to read the next calendar component from the file
      */
     private function _next_component()
     {
         $buffer = '';
         $vcalendar_head = false;
         while (($line = fgets($this->fp, 1024)) !== false) {
             // ignore END:VCALENDAR lines
             if (preg_match('/END:VCALENDAR/i', $line)) {
                 continue;
             }
             // read vcalendar header (with timezone defintion)
             if (preg_match('/BEGIN:VCALENDAR/i', $line)) {
                 $this->vhead = '';
                 $vcalendar_head = true;
             }
 
             // end of VCALENDAR header part
             if ($vcalendar_head && preg_match('/BEGIN:(VEVENT|VTODO|VFREEBUSY)/i', $line)) {
                 $vcalendar_head = false;
             }
 
             if ($vcalendar_head) {
                 $this->vhead .= $line;
             }
             else {
                 $buffer .= $line;
                 if (preg_match('/END:(VEVENT|VTODO|VFREEBUSY)/i', $line)) {
                     break;
                 }
             }
         }
 
         return $buffer;
     }
 
     /**
      * Import objects from an already parsed Sabre\VObject\Component object
      *
      * @param object Sabre\VObject\Component to read from
      * @return array List of events extracted from the file
      */
     public function import_from_vobject($vobject)
     {
         $seen = array();
         $exceptions = array();
 
         if ($vobject->name == 'VCALENDAR') {
             $this->method = strval($vobject->METHOD);
             $this->agent  = strval($vobject->PRODID);
 
             foreach ($vobject->getBaseComponents() ?: $vobject->getComponents() as $ve) {
                 if ($ve->name == 'VEVENT' || $ve->name == 'VTODO') {
                     // convert to hash array representation
                     $object = $this->_to_array($ve);
 
                     // temporarily store this as exception
                     if ($object['recurrence_date']) {
                         $exceptions[] = $object;
                     }
                     else if (!$seen[$object['uid']]++) {
                         $this->objects[] = $object;
                     }
                 }
                 else if ($ve->name == 'VFREEBUSY') {
                     $this->objects[] = $this->_parse_freebusy($ve);
                 }
             }
 
             // add exceptions to the according master events
             foreach ($exceptions as $exception) {
                 $uid = $exception['uid'];
 
                 // make this exception the master
                 if (!$seen[$uid]++) {
                     $this->objects[] = $exception;
                 }
                 else {
                     foreach ($this->objects as $i => $object) {
                         // add as exception to existing entry with a matching UID
                         if ($object['uid'] == $uid) {
                             $this->objects[$i]['exceptions'][] = $exception;
 
                             if (!empty($object['recurrence'])) {
                                 $this->objects[$i]['recurrence']['EXCEPTIONS'] = &$this->objects[$i]['exceptions'];
                             }
                             break;
                         }
                     }
                 }
             }
         }
 
         return $this->objects;
     }
 
     /**
      * Getter for free-busy periods
      */
     public function get_busy_periods()
     {
         $out = array();
         foreach ((array)$this->freebusy['periods'] as $period) {
             if ($period[2] != 'FREE') {
                 $out[] = $period;
             }
         }
 
         return $out;
     }
 
     /**
      * Helper method to determine whether the connected client is an Apple device
      */
     private function is_apple()
     {
         return stripos($this->agent, 'Apple') !== false
             || stripos($this->agent, 'Mac OS X') !== false
             || stripos($this->agent, 'iOS/') !== false;
     }
 
     /**
      * Convert the given VEvent object to a libkolab compatible array representation
      *
      * @param object Vevent object to convert
      * @return array Hash array with object properties
      */
     private function _to_array($ve)
     {
         $event = array(
             'uid'     => self::convert_string($ve->UID),
             'title'   => self::convert_string($ve->SUMMARY),
             '_type'   => $ve->name == 'VTODO' ? 'task' : 'event',
             // set defaults
             'priority' => 0,
             'attendees' => array(),
             'x-custom' => array(),
         );
 
         // Catch possible exceptions when date is invalid (Bug #2144)
         // We can skip these fields, they aren't critical
         foreach (array('CREATED' => 'created', 'LAST-MODIFIED' => 'changed', 'DTSTAMP' => 'changed') as $attr => $field) {
             try {
                 if (!$event[$field] && $ve->{$attr}) {
                     $event[$field] = $ve->{$attr}->getDateTime();
                 }
             } catch (Exception $e) {}
         }
 
         // map other attributes to internal fields
         foreach ($ve->children as $prop) {
             if (!($prop instanceof VObject\Property))
                 continue;
 
             switch ($prop->name) {
             case 'DTSTART':
             case 'DTEND':
             case 'DUE':
                 $propmap = array('DTSTART' => 'start', 'DTEND' => 'end', 'DUE' => 'due');
                 $event[$propmap[$prop->name]] =  self::convert_datetime($prop);
                 break;
 
             case 'TRANSP':
                 $event['free_busy'] = $prop->value == 'TRANSPARENT' ? 'free' : 'busy';
                 break;
 
             case 'STATUS':
                 if ($prop->value == 'TENTATIVE')
                     $event['free_busy'] = 'tentative';
                 else if ($prop->value == 'CANCELLED')
                     $event['cancelled'] = true;
                 else if ($prop->value == 'COMPLETED')
                     $event['complete'] = 100;
 
                 $event['status'] = strval($prop->value);
                 break;
 
             case 'COMPLETED':
                 if (self::convert_datetime($prop)) {
                     $event['status'] = 'COMPLETED';
                     $event['complete'] = 100;
                 }
                 break;
 
             case 'PRIORITY':
                 if (is_numeric($prop->value))
                     $event['priority'] = $prop->value;
                 break;
 
             case 'RRULE':
                 $params = is_array($event['recurrence']) ? $event['recurrence'] : array();
                 // parse recurrence rule attributes
                 foreach (explode(';', $prop->value) as $par) {
                     list($k, $v) = explode('=', $par);
                     $params[$k] = $v;
                 }
                 if ($params['UNTIL'])
                     $params['UNTIL'] = date_create($params['UNTIL']);
                 if (!$params['INTERVAL'])
                     $params['INTERVAL'] = 1;
 
                 $event['recurrence'] = array_filter($params);
                 break;
 
             case 'EXDATE':
                 if (!empty($prop->value))
                     $event['recurrence']['EXDATE'] = array_merge((array)$event['recurrence']['EXDATE'], self::convert_datetime($prop, true));
                 break;
 
             case 'RDATE':
                 if (!empty($prop->value))
                     $event['recurrence']['RDATE'] = array_merge((array)$event['recurrence']['RDATE'], self::convert_datetime($prop, true));
                 break;
 
             case 'RECURRENCE-ID':
                 $event['recurrence_date'] = self::convert_datetime($prop);
                 if ($prop->offsetGet('RANGE') == 'THISANDFUTURE' || $prop->offsetGet('THISANDFUTURE') !== null) {
                     $event['thisandfuture'] = true;
                 }
                 break;
 
             case 'RELATED-TO':
                 $reltype = $prop->offsetGet('RELTYPE');
                 if ($reltype == 'PARENT' || $reltype === null) {
                     $event['parent_id'] = $prop->value;
                 }
                 break;
 
             case 'SEQUENCE':
                 $event['sequence'] = intval($prop->value);
                 break;
 
             case 'PERCENT-COMPLETE':
                 $event['complete'] = intval($prop->value);
                 break;
 
             case 'LOCATION':
             case 'DESCRIPTION':
             case 'URL':
             case 'COMMENT':
                 $event[strtolower($prop->name)] = self::convert_string($prop);
                 break;
 
             case 'CATEGORY':
             case 'CATEGORIES':
                 $event['categories'] = array_merge((array)$event['categories'], $prop->getParts());
                 break;
 
             case 'CLASS':
             case 'X-CALENDARSERVER-ACCESS':
                 $event['sensitivity'] = strtolower($prop->value);
                 break;
 
             case 'X-MICROSOFT-CDO-BUSYSTATUS':
                 if ($prop->value == 'OOF')
                     $event['free_busy'] = 'outofoffice';
                 else if (in_array($prop->value, array('FREE', 'BUSY', 'TENTATIVE')))
                     $event['free_busy'] = strtolower($prop->value);
                 break;
 
             case 'ATTENDEE':
             case 'ORGANIZER':
                 $params = array('rsvp' => false);
                 foreach ($prop->parameters as $param) {
                     switch ($param->name) {
                         case 'RSVP': $params[$param->name] = strtolower($param->value) == 'true'; break;
                         default:     $params[$param->name] = $param->value; break;
                     }
                 }
                 $attendee = self::map_keys($params, array_flip($this->attendee_keymap));
                 $attendee['email'] = preg_replace('/^mailto:/i', '', $prop->value);
 
                 if ($prop->name == 'ORGANIZER') {
                     $attendee['role'] = 'ORGANIZER';
                     $attendee['status'] = 'ACCEPTED';
                     $event['organizer'] = $attendee;
                 }
                 else if ($attendee['email'] != $event['organizer']['email']) {
                     $event['attendees'][] = $attendee;
                 }
                 break;
 
             case 'ATTACH':
                 $params = self::parameters_array($prop);
                 if (substr($prop->value, 0, 4) == 'http' && !strpos($prop->value, ':attachment:')) {
                     $event['links'][] = $prop->value;
                 }
                 else if (strlen($prop->value) && strtoupper($params['VALUE']) == 'BINARY') {
                     $attachment = self::map_keys($params, array('FMTTYPE' => 'mimetype', 'X-LABEL' => 'name'));
                     $attachment['data'] = base64_decode($prop->value);
                     $attachment['size'] = strlen($attachment['data']);
                     $event['attachments'][] = $attachment;
                 }
                 break;
 
             default:
                 if (substr($prop->name, 0, 2) == 'X-')
                     $event['x-custom'][] = array($prop->name, strval($prop->value));
                 break;
             }
         }
 
         // check DURATION property if no end date is set
         if (empty($event['end']) && $ve->DURATION) {
             try {
                 $duration = new DateInterval(strval($ve->DURATION));
                 $end = clone $event['start'];
                 $end->add($duration);
                 $event['end'] = $end;
             }
             catch (\Exception $e) {
                 trigger_error(strval($e), E_USER_WARNING);
             }
         }
 
         // validate event dates
         if ($event['_type'] == 'event') {
             // check for all-day dates
             if ($event['start']->_dateonly) {
                 $event['allday'] = true;
             }
 
             // all-day events may lack the DTEND property
             if ($event['allday'] && empty($event['end'])) {
                 $event['end'] = clone $event['start'];
             }
             // shift end-date by one day (except Thunderbird)
             else if ($event['allday'] && is_object($event['end'])) {
                 $event['end']->sub(new \DateInterval('PT23H'));
             }
 
             // sanity-check and fix end date
             if (!empty($event['end']) && $event['end'] < $event['start']) {
                 $event['end'] = clone $event['start'];
             }
         }
 
         // make organizer part of the attendees list for compatibility reasons
         if (!empty($event['organizer']) && is_array($event['attendees']) && $event['_type'] == 'event') {
             array_unshift($event['attendees'], $event['organizer']);
         }
 
         // find alarms
         foreach ($ve->select('VALARM') as $valarm) {
-            $action = 'DISPLAY';
+            $action  = 'DISPLAY';
             $trigger = null;
-            $alarm = array();
+            $alarm   = array();
 
             foreach ($valarm->children as $prop) {
                 switch ($prop->name) {
                 case 'TRIGGER':
                     foreach ($prop->parameters as $param) {
                         if ($param->name == 'VALUE' && $param->value == 'DATE-TIME') {
                             $trigger = '@' . $prop->getDateTime()->format('U');
                             $alarm['trigger'] = $prop->getDateTime();
                         }
+                        else if ($param->name == 'RELATED') {
+                            $alarm['related'] = $param->value;
+                        }
                     }
                     if (!$trigger && ($values = libcalendaring::parse_alarm_value($prop->value))) {
                         $trigger = $values[2];
                     }
 
                     if (!$alarm['trigger']) {
                         $alarm['trigger'] = rtrim(preg_replace('/([A-Z])0[WDHMS]/', '\\1', $prop->value), 'T');
                         // if all 0-values have been stripped, assume 'at time'
                         if ($alarm['trigger'] == 'P')
                             $alarm['trigger'] = 'PT0S';
                     }
                     break;
 
                 case 'ACTION':
                     $action = $alarm['action'] = strtoupper($prop->value);
                     break;
 
                 case 'SUMMARY':
                 case 'DESCRIPTION':
                 case 'DURATION':
                     $alarm[strtolower($prop->name)] = self::convert_string($prop);
                     break;
 
                 case 'REPEAT':
                     $alarm['repeat'] = intval($prop->value);
                     break;
 
                 case 'ATTENDEE':
                     $alarm['attendees'][] = preg_replace('/^mailto:/i', '', $prop->value);
                     break;
 
                 case 'ATTACH':
                     $params = self::parameters_array($prop);
                     if (strlen($prop->value) && (preg_match('/^[a-z]+:/', $prop->value) || strtoupper($params['VALUE']) == 'URI')) {
                         // we only support URI-type of attachments here
                         $alarm['uri'] = $prop->value;
                     }
                     break;
                 }
             }
 
             if ($action != 'NONE') {
                 if ($trigger && !$event['alarms']) // store first alarm in legacy property
                     $event['alarms'] = $trigger . ':' . $action;
 
                 if ($alarm['trigger'])
                     $event['valarms'][] = $alarm;
             }
         }
 
         // assign current timezone to event start/end
         if ($event['start'] instanceof DateTime) {
             if ($this->timezone)
                 $event['start']->setTimezone($this->timezone);
         }
         else {
             unset($event['start']);
         }
 
         if ($event['end'] instanceof DateTime) {
             if ($this->timezone)
                 $event['end']->setTimezone($this->timezone);
         }
         else {
             unset($event['end']);
         }
 
         // minimal validation
         if (empty($event['uid']) || ($event['_type'] == 'event' && empty($event['start']) != empty($event['end']))) {
             throw new VObject\ParseException('Object validation failed: missing mandatory object properties');
         }
 
         return $event;
     }
 
     /**
      * Parse the given vfreebusy component into an array representation
      */
     private function _parse_freebusy($ve)
     {
         $this->freebusy = array('_type' => 'freebusy', 'periods' => array());
         $seen = array();
 
         foreach ($ve->children as $prop) {
             if (!($prop instanceof VObject\Property))
                 continue;
 
             switch ($prop->name) {
             case 'CREATED':
             case 'LAST-MODIFIED':
             case 'DTSTAMP':
             case 'DTSTART':
             case 'DTEND':
                 $propmap = array('DTSTART' => 'start', 'DTEND' => 'end', 'CREATED' => 'created', 'LAST-MODIFIED' => 'changed', 'DTSTAMP' => 'changed');
                 $this->freebusy[$propmap[$prop->name]] =  self::convert_datetime($prop);
                 break;
 
             case 'ORGANIZER':
                 $this->freebusy['organizer'] = preg_replace('/^mailto:/i', '', $prop->value);
                 break;
 
             case 'FREEBUSY':
                 // The freebusy component can hold more than 1 value, separated by commas.
                 $periods = explode(',', $prop->value);
                 $fbtype = strval($prop['FBTYPE']) ?: 'BUSY';
 
                 // skip dupes
                 if ($seen[$prop->value.':'.$fbtype]++)
                     continue;
 
                 foreach ($periods as $period) {
                     // Every period is formatted as [start]/[end]. The start is an
                     // absolute UTC time, the end may be an absolute UTC time, or
                     // duration (relative) value.
                     list($busyStart, $busyEnd) = explode('/', $period);
 
                     $busyStart = VObject\DateTimeParser::parse($busyStart);
                     $busyEnd = VObject\DateTimeParser::parse($busyEnd);
                     if ($busyEnd instanceof \DateInterval) {
                         $tmp = clone $busyStart;
                         $tmp->add($busyEnd);
                         $busyEnd = $tmp;
                     }
 
                     if ($busyEnd && $busyEnd > $busyStart)
                         $this->freebusy['periods'][] = array($busyStart, $busyEnd, $fbtype);
                 }
                 break;
 
             case 'COMMENT':
                 $this->freebusy['comment'] = $prop->value;
             }
         }
 
         return $this->freebusy;
     }
 
     /**
      *
      */
     public static function convert_string($prop)
     {
         return str_replace('\,', ',', strval($prop->value));
     }
 
     /**
      * Helper method to correctly interpret an all-day date value
      */
     public static function convert_datetime($prop, $as_array = false)
     {
         if (empty($prop)) {
             return $as_array ? array() : null;
         }
         else if ($prop instanceof VObject\Property\MultiDateTime) {
             $dt = array();
             $dateonly = ($prop->getDateType() & VObject\Property\DateTime::DATE);
             foreach ($prop->getDateTimes() as $item) {
                 $item->_dateonly = $dateonly;
                 $dt[] = $item;
             }
         }
         else if ($prop instanceof VObject\Property\DateTime) {
             $dt = $prop->getDateTime();
             if ($prop->getDateType() & VObject\Property\DateTime::DATE) {
                 $dt->_dateonly = true;
             }
         }
         else if ($prop instanceof VObject\Property && ($prop['VALUE'] == 'DATE' || $prop['VALUE'] == 'DATE-TIME')) {
             try {
                 list($type, $dt) = VObject\Property\DateTime::parseData($prop->value, $prop);
                 $dt->_dateonly = ($type & VObject\Property\DateTime::DATE);
             }
             catch (Exception $e) {
                 // ignore date parse errors
             }
         }
         else if ($prop instanceof VObject\Property && $prop['VALUE'] == 'PERIOD') {
             $dt = array();
             foreach(explode(',', $prop->value) as $val) {
                 try {
                     list($start, $end) = explode('/', $val);
                     list($type, $item) = VObject\Property\DateTime::parseData($start, $prop);
                     $item->_dateonly = ($type & VObject\Property\DateTime::DATE);
                     $dt[] = $item;
                 }
                 catch (Exception $e) {
                     // ignore single date parse errors
                 }
             }
         }
         else if ($prop instanceof DateTime) {
             $dt = $prop;
         }
 
         // force return value to array if requested
         if ($as_array && !is_array($dt)) {
             $dt = empty($dt) ? array() : array($dt);
         }
 
         return $dt;
     }
 
 
     /**
      * Create a Sabre\VObject\Property instance from a PHP DateTime object
      *
      * @param string Property name
      * @param object DateTime
      */
     public function datetime_prop($name, $dt, $utc = false, $dateonly = null)
     {
         $is_utc = $utc || (($tz = $dt->getTimezone()) && in_array($tz->getName(), array('UTC','GMT','Z')));
         $is_dateonly = $dateonly === null ? (bool)$dt->_dateonly : (bool)$dateonly;
         $vdt = new VObject\Property\DateTime($name);
         $vdt->setDateTime($dt, $is_dateonly ? VObject\Property\DateTime::DATE :
             ($is_utc ? VObject\Property\DateTime::UTC : VObject\Property\DateTime::LOCALTZ));
 
         // register timezone for VTIMEZONE block
         if (!$is_utc && !$dateonly && $tz && ($tzname = $tz->getName())) {
             $ts = $dt->format('U');
             if (is_array($this->vtimezones[$tzname])) {
                 $this->vtimezones[$tzname][0] = min($this->vtimezones[$tzname][0], $ts);
                 $this->vtimezones[$tzname][1] = max($this->vtimezones[$tzname][1], $ts);
             }
             else {
                 $this->vtimezones[$tzname] = array($ts, $ts);
             }
         }
 
         return $vdt;
     }
 
     /**
      * Copy values from one hash array to another using a key-map
      */
     public static function map_keys($values, $map)
     {
         $out = array();
         foreach ($map as $from => $to) {
             if (isset($values[$from]))
                 $out[$to] = is_array($values[$from]) ? join(',', $values[$from]) : $values[$from];
         }
         return $out;
     }
 
     /**
      *
      */
     private static function parameters_array($prop)
     {
         $params = array();
         foreach ($prop->parameters as $param) {
             $params[strtoupper($param->name)] = $param->value;
         }
         return $params;
     }
 
 
     /**
      * Export events to iCalendar format
      *
      * @param  array   Events as array
      * @param  string  VCalendar method to advertise
      * @param  boolean Directly send data to stdout instead of returning
      * @param  callable Callback function to fetch attachment contents, false if no attachment export
      * @param  boolean Add VTIMEZONE block with timezone definitions for the included events
      * @return string  Events in iCalendar format (http://tools.ietf.org/html/rfc5545)
      */
     public function export($objects, $method = null, $write = false, $get_attachment = false, $with_timezones = true)
     {
         $this->method = $method;
 
         // encapsulate in VCALENDAR container
         $vcal = VObject\Component::create('VCALENDAR');
         $vcal->version = '2.0';
         $vcal->prodid = $this->prodid;
         $vcal->calscale = 'GREGORIAN';
 
         if (!empty($method)) {
             $vcal->METHOD = $method;
         }
 
         // write vcalendar header
         if ($write) {
             echo preg_replace('/END:VCALENDAR[\r\n]*$/m', '', $vcal->serialize());
         }
 
         foreach ($objects as $object) {
             $this->_to_ical($object, !$write?$vcal:false, $get_attachment);
         }
 
         // include timezone information
         if ($with_timezones || !empty($method)) {
             foreach ($this->vtimezones as $tzid => $range) {
                 $vt = self::get_vtimezone($tzid, $range[0], $range[1]);
                 if (empty($vt)) {
                     continue;  // no timezone information found
                 }
 
                 if ($write) {
                     echo $vt->serialize();
                 }
                 else {
                     $vcal->add($vt);
                 }
             }
         }
 
         if ($write) {
             echo "END:VCALENDAR\r\n";
             return true;
         }
         else {
             return $vcal->serialize();
         }
     }
 
     /**
      * Build a valid iCal format block from the given event
      *
      * @param  array    Hash array with event/task properties from libkolab
      * @param  object   VCalendar object to append event to or false for directly sending data to stdout
      * @param  callable Callback function to fetch attachment contents, false if no attachment export
      * @param  object   RECURRENCE-ID property when serializing a recurrence exception
      */
     private function _to_ical($event, $vcal, $get_attachment, $recurrence_id = null)
     {
         $type = $event['_type'] ?: 'event';
         $ve = VObject\Component::create($this->type_component_map[$type]);
         $ve->add('UID', $event['uid']);
 
         // set DTSTAMP according to RFC 5545, 3.8.7.2.
         $dtstamp = !empty($event['changed']) && !empty($this->method) ? $event['changed'] : new DateTime();
         $ve->add($this->datetime_prop('DTSTAMP', $dtstamp, true));
 
         // all-day events end the next day
         if ($event['allday'] && !empty($event['end'])) {
             $event['end'] = clone $event['end'];
             $event['end']->add(new \DateInterval('P1D'));
             $event['end']->_dateonly = true;
         }
         if (!empty($event['created']))
             $ve->add($this->datetime_prop('CREATED', $event['created'], true));
         if (!empty($event['changed']))
             $ve->add($this->datetime_prop('LAST-MODIFIED', $event['changed'], true));
         if (!empty($event['start']))
             $ve->add($this->datetime_prop('DTSTART', $event['start'], false, (bool)$event['allday']));
         if (!empty($event['end']))
             $ve->add($this->datetime_prop('DTEND',   $event['end'], false, (bool)$event['allday']));
         if (!empty($event['due']))
             $ve->add($this->datetime_prop('DUE',   $event['due'], false));
 
         // we're exporting a recurrence instance only
         if (!$recurrence_id && $event['recurrence_date'] && $event['recurrence_date'] instanceof DateTime) {
             $recurrence_id = $this->datetime_prop('RECURRENCE-ID', $event['recurrence_date'], false, (bool)$event['allday']);
             if ($event['thisandfuture'])
                 $recurrence_id->add('RANGE', 'THISANDFUTURE');
         }
 
         if ($recurrence_id)
             $ve->add($recurrence_id);
 
         $ve->add('SUMMARY', $event['title']);
 
         if ($event['location'])
             $ve->add($this->is_apple() ? new vobject_location_property('LOCATION', $event['location']) : new VObject\Property('LOCATION', $event['location']));
         if ($event['description'])
             $ve->add('DESCRIPTION', strtr($event['description'], array("\r\n" => "\n", "\r" => "\n"))); // normalize line endings
 
         if (isset($event['sequence']))
             $ve->add('SEQUENCE', $event['sequence']);
 
         if ($event['recurrence'] && !$recurrence_id) {
             $exdates = $rdates = null;
             if (isset($event['recurrence']['EXDATE'])) {
                 $exdates = $event['recurrence']['EXDATE'];
                 unset($event['recurrence']['EXDATE']);  // don't serialize EXDATEs into RRULE value
             }
             if (isset($event['recurrence']['RDATE'])) {
                 $rdates = $event['recurrence']['RDATE'];
                 unset($event['recurrence']['RDATE']);  // don't serialize RDATEs into RRULE value
             }
 
             if ($event['recurrence']['FREQ']) {
                 $ve->add('RRULE', libcalendaring::to_rrule($event['recurrence'], (bool)$event['allday']));
             }
 
             // add EXDATEs each one per line (for Thunderbird Lightning)
             if (is_array($exdates)) {
                 foreach ($exdates as $ex) {
                     if ($ex instanceof \DateTime) {
                         $exd = clone $event['start'];
                         $exd->setDate($ex->format('Y'), $ex->format('n'), $ex->format('j'));
                         $exd->setTimeZone(new \DateTimeZone('UTC'));
                         $ve->add(new VObject\Property('EXDATE', $exd->format('Ymd\\THis\\Z')));
                     }
                 }
             }
             // add RDATEs
             if (is_array($rdates) && !empty($rdates)) {
                 $sample = $this->datetime_prop('RDATE', $rdates[0]);
                 $rdprop = new VObject\Property\MultiDateTime('RDATE', null);
                 $rdprop->setDateTimes($rdates, $sample->getDateType());
                 $ve->add($rdprop);
             }
         }
 
         if ($event['categories']) {
             $cat = VObject\Property::create('CATEGORIES');
             $cat->setParts((array)$event['categories']);
             $ve->add($cat);
         }
 
         if (!empty($event['free_busy'])) {
             $ve->add('TRANSP', $event['free_busy'] == 'free' ? 'TRANSPARENT' : 'OPAQUE');
 
             // for Outlook clients we provide the X-MICROSOFT-CDO-BUSYSTATUS property
             if (stripos($this->agent, 'outlook') !== false) {
                 $ve->add('X-MICROSOFT-CDO-BUSYSTATUS', $event['free_busy'] == 'outofoffice' ? 'OOF' : strtoupper($event['free_busy']));
             }
         }
 
         if ($event['priority'])
           $ve->add('PRIORITY', $event['priority']);
 
         if ($event['cancelled'])
             $ve->add('STATUS', 'CANCELLED');
         else if ($event['free_busy'] == 'tentative')
             $ve->add('STATUS', 'TENTATIVE');
         else if ($event['complete'] == 100)
             $ve->add('STATUS', 'COMPLETED');
         else if (!empty($event['status']))
             $ve->add('STATUS', $event['status']);
 
         if (!empty($event['sensitivity']))
             $ve->add('CLASS', strtoupper($event['sensitivity']));
 
         if (!empty($event['complete'])) {
             $ve->add('PERCENT-COMPLETE', intval($event['complete']));
         }
 
         // Apple iCal and BusyCal required the COMPLETED date to be set in order to consider a task complete
         if ($event['status'] == 'COMPLETED' || $event['complete'] == 100) {
             $ve->add($this->datetime_prop('COMPLETED', $event['changed'] ?: new DateTime('now - 1 hour'), true));
         }
 
         if ($event['valarms']) {
             foreach ($event['valarms'] as $alarm) {
                 $va = VObject\Component::create('VALARM');
                 $va->action = $alarm['action'];
                 if ($alarm['trigger'] instanceof DateTime) {
                     $va->add($this->datetime_prop('TRIGGER', $alarm['trigger'], true));
                 }
                 else {
-                    $va->add('TRIGGER', $alarm['trigger']);
+                    $alarm_props = array();
+                    if (strtoupper($alarm['related']) == 'END') {
+                        $alarm_props['RELATED'] = 'END';
+                    }
+                    $va->add('TRIGGER', $alarm['trigger'], $alarm_props);
                 }
 
                 if ($alarm['action'] == 'EMAIL') {
                     foreach ((array)$alarm['attendees'] as $attendee) {
                         $va->add('ATTENDEE', 'mailto:' . $attendee);
                     }
                 }
                 if ($alarm['description']) {
                     $va->add('DESCRIPTION', $alarm['description'] ?: $event['title']);
                 }
                 if ($alarm['summary']) {
                     $va->add('SUMMARY', $alarm['summary']);
                 }
                 if ($alarm['duration']) {
                     $va->add('DURATION', $alarm['duration']);
                     $va->add('REPEAT', intval($alarm['repeat']));
                 }
                 if ($alarm['uri']) {
                     $va->add('ATTACH', $alarm['uri'], array('VALUE' => 'URI'));
                 }
                 $ve->add($va);
             }
         }
         // legacy support
         else if ($event['alarms']) {
             $va = VObject\Component::create('VALARM');
             list($trigger, $va->action) = explode(':', $event['alarms']);
             $val = libcalendaring::parse_alarm_value($trigger);
             if ($val[3])
                 $va->add('TRIGGER', $val[3]);
             else if ($val[0] instanceof DateTime)
                 $va->add($this->datetime_prop('TRIGGER', $val[0]));
             $ve->add($va);
         }
 
         foreach ((array)$event['attendees'] as $attendee) {
             if ($attendee['role'] == 'ORGANIZER') {
                 if (empty($event['organizer']))
                     $event['organizer'] = $attendee;
             }
             else if (!empty($attendee['email'])) {
                 if (isset($attendee['rsvp']))
                     $attendee['rsvp'] = $attendee['rsvp'] ? 'TRUE' : null;
                 $ve->add('ATTENDEE', 'mailto:' . $attendee['email'], array_filter(self::map_keys($attendee, $this->attendee_keymap)));
             }
         }
 
         if ($event['organizer']) {
             $ve->add('ORGANIZER', 'mailto:' . $event['organizer']['email'], self::map_keys($event['organizer'], array('name' => 'CN')));
         }
 
         foreach ((array)$event['url'] as $url) {
             if (!empty($url)) {
                 $ve->add('URL', $url);
             }
         }
 
         if (!empty($event['parent_id'])) {
             $ve->add('RELATED-TO', $event['parent_id'], array('RELTYPE' => 'PARENT'));
         }
 
         if ($event['comment'])
             $ve->add('COMMENT', $event['comment']);
 
         $memory_limit = parse_bytes(ini_get('memory_limit'));
 
         // export attachments
         if (!empty($event['attachments'])) {
             foreach ((array)$event['attachments'] as $attach) {
                 // check available memory and skip attachment export if we can't buffer it
                 // @todo: use rcube_utils::mem_check()
                 if (is_callable($get_attachment) && $memory_limit > 0 && ($memory_used = function_exists('memory_get_usage') ? memory_get_usage() : 16*1024*1024)
                     && $attach['size'] && $memory_used + $attach['size'] * 3 > $memory_limit) {
                     continue;
                 }
                 // embed attachments using the given callback function
                 if (is_callable($get_attachment) && ($data = call_user_func($get_attachment, $attach['id'], $event))) {
                     // embed attachments for iCal
                     $ve->add('ATTACH',
                         base64_encode($data),
                         array_filter(array('VALUE' => 'BINARY', 'ENCODING' => 'BASE64', 'FMTTYPE' => $attach['mimetype'], 'X-LABEL' => $attach['name'])));
                     unset($data);  // attempt to free memory
                 }
                 // list attachments as absolute URIs
                 else if (!empty($this->attach_uri)) {
                     $ve->add('ATTACH',
                         strtr($this->attach_uri, array(
                             '{{id}}'       => urlencode($attach['id']),
                             '{{name}}'     => urlencode($attach['name']),
                             '{{mimetype}}' => urlencode($attach['mimetype']),
                         )),
                         array('FMTTYPE' => $attach['mimetype'], 'VALUE' => 'URI'));
                 }
             }
         }
 
         foreach ((array)$event['links'] as $uri) {
             $ve->add('ATTACH', $uri);
         }
 
         // add custom properties
         foreach ((array)$event['x-custom'] as $prop) {
             $ve->add($prop[0], $prop[1]);
         }
 
         // append to vcalendar container
         if ($vcal) {
             $vcal->add($ve);
         }
         else {   // serialize and send to stdout
             echo $ve->serialize();
         }
 
         // append recurrence exceptions
         if (is_array($event['recurrence']) && $event['recurrence']['EXCEPTIONS']) {
             foreach ($event['recurrence']['EXCEPTIONS'] as $ex) {
                 $exdate = $ex['recurrence_date'] ?: $ex['start'];
                 $recurrence_id = $this->datetime_prop('RECURRENCE-ID', $exdate, false, (bool)$event['allday']);
                 if ($ex['thisandfuture'])
                     $recurrence_id->add('RANGE', 'THISANDFUTURE');
                 $this->_to_ical($ex, $vcal, $get_attachment, $recurrence_id);
             }
         }
     }
 
     /**
      * Returns a VTIMEZONE component for a Olson timezone identifier
      * with daylight transitions covering the given date range.
      *
      * @param string Timezone ID as used in PHP's Date functions
      * @param integer Unix timestamp with first date/time in this timezone
      * @param integer Unix timestap with last date/time in this timezone
      *
      * @return mixed A Sabre\VObject\Component object representing a VTIMEZONE definition
      *               or false if no timezone information is available
      */
     public static function get_vtimezone($tzid, $from = 0, $to = 0)
     {
         if (!$from) $from = time();
         if (!$to)   $to = $from;
 
         if (is_string($tzid)) {
             try {
                 $tz = new \DateTimeZone($tzid);
             }
             catch (\Exception $e) {
                 return false;
             }
         }
         else if (is_a($tzid, '\\DateTimeZone')) {
             $tz = $tzid;
         }
 
         if (!is_a($tz, '\\DateTimeZone')) {
             return false;
         }
 
         $year = 86400 * 360;
         $transitions = $tz->getTransitions($from - $year, $to + $year);
 
         $vt = new VObject\Component('VTIMEZONE');
         $vt->TZID = $tz->getName();
 
         $std = null; $dst = null;
         foreach ($transitions as $i => $trans) {
             $cmp = null;
 
             if ($i == 0) {
                 $tzfrom = $trans['offset'] / 3600;
                 continue;
             }
 
             if ($trans['isdst']) {
                 $t_dst = $trans['ts'];
                 $dst = new VObject\Component('DAYLIGHT');
                 $cmp = $dst;
             }
             else {
                 $t_std = $trans['ts'];
                 $std = new VObject\Component('STANDARD');
                 $cmp = $std;
             }
 
             if ($cmp) {
                 $dt = new DateTime($trans['time']);
                 $offset = $trans['offset'] / 3600;
 
                 $cmp->DTSTART = $dt->format('Ymd\THis');
                 $cmp->TZOFFSETFROM = sprintf('%s%02d%02d', $tzfrom >= 0 ? '+' : '', floor($tzfrom), ($tzfrom - floor($tzfrom)) * 60);
                 $cmp->TZOFFSETTO   = sprintf('%s%02d%02d', $offset >= 0 ? '+' : '', floor($offset), ($offset - floor($offset)) * 60);
 
                 if (!empty($trans['abbr'])) {
                     $cmp->TZNAME = $trans['abbr'];
                 }
 
                 $tzfrom = $offset;
                 $vt->add($cmp);
             }
 
             // we covered the entire date range
             if ($std && $dst && min($t_std, $t_dst) < $from && max($t_std, $t_dst) > $to) {
                 break;
             }
         }
 
         // add X-MICROSOFT-CDO-TZID if available
         $microsoftExchangeMap = array_flip(VObject\TimeZoneUtil::$microsoftExchangeMap);
         if (array_key_exists($tz->getName(), $microsoftExchangeMap)) {
             $vt->add('X-MICROSOFT-CDO-TZID', $microsoftExchangeMap[$tz->getName()]);
         }
 
         return $vt;
     }
 
 
     /*** Implement PHP 5 Iterator interface to make foreach work ***/
 
     function current()
     {
         return $this->objects[$this->iteratorkey];
     }
 
     function key()
     {
         return $this->iteratorkey;
     }
 
     function next()
     {
         $this->iteratorkey++;
 
         // read next chunk if we're reading from a file
         if (!$this->objects[$this->iteratorkey] && $this->fp) {
             $this->_parse_next(true);
         }
 
         return $this->valid();
     }
 
     function rewind()
     {
         $this->iteratorkey = 0;
     }
 
     function valid()
     {
         return !empty($this->objects[$this->iteratorkey]);
     }
 
 }
 
 
 /**
  * Override Sabre\VObject\Property that quotes commas in the location property
  * because Apple clients treat that property as list.
  */
 class vobject_location_property extends VObject\Property
 {
     /**
      * Turns the object back into a serialized blob.
      *
      * @return string
      */
     public function serialize()
     {
         $str = $this->name;
 
         foreach ($this->parameters as $param) {
             $str.=';' . $param->serialize();
         }
 
         $src = array(
             '\\',
             "\n",
             ',',
         );
         $out = array(
             '\\\\',
             '\n',
             '\,',
         );
         $str.=':' . str_replace($src, $out, $this->value);
 
         $out = '';
         while (strlen($str) > 0) {
             if (strlen($str) > 75) {
                 $out.= mb_strcut($str, 0, 75, 'utf-8') . "\r\n";
                 $str = ' ' . mb_strcut($str, 75, strlen($str), 'utf-8');
             } else {
                 $out.= $str . "\r\n";
                 $str = '';
                 break;
             }
         }
 
         return $out;
     }
 }
diff --git a/plugins/libcalendaring/localization/en_US.inc b/plugins/libcalendaring/localization/en_US.inc
index 00a01f5b..b0a3585e 100644
--- a/plugins/libcalendaring/localization/en_US.inc
+++ b/plugins/libcalendaring/localization/en_US.inc
@@ -1,166 +1,176 @@
 <?php
 
 /**
  * Localizations for the Kolab calendaring utilities plugin
  *
  * Copyright (C) 2014, Kolab Systems AG
  *
  * For translation see https://www.transifex.com/projects/p/kolab/resource/libcalendaring/
  */
 
 $labels = array();
 
 // words for spoken dates
 $labels['until'] = 'until';
 $labels['at'] = 'at';
 
 // alarms related labels
 $labels['alarmemail'] = 'Send Email';
 $labels['alarmdisplay'] = 'Show message';
 $labels['alarmaudio'] = 'Play sound';
 $labels['alarmdisplayoption'] = 'Message';
 $labels['alarmemailoption'] = 'Email';
 $labels['alarmaudiooption'] = 'Sound';
 $labels['alarmat'] = 'at $datetime';
 $labels['trigger@'] = 'on date';
 $labels['trigger-M'] = 'minutes before';
 $labels['trigger-H'] = 'hours before';
 $labels['trigger-D'] = 'days before';
 $labels['trigger+M'] = 'minutes after';
 $labels['trigger+H'] = 'hours after';
 $labels['trigger+D'] = 'days after';
+$labels['triggerend-M'] = 'minutes before end';
+$labels['triggerend-H'] = 'hours before end';
+$labels['triggerend-D'] = 'days before end';
+$labels['triggerend+M'] = 'minutes after end';
+$labels['triggerend+H'] = 'hours after end';
+$labels['triggerend+D'] = 'days after end';
 $labels['trigger0'] = 'on time';
-$labels['triggerattime'] = 'at time';
+$labels['triggerattime'] = 'at start time';
+$labels['triggerattimeend'] = 'at end time';
+$labels['relatedstart'] = 'start';
+$labels['relatedendevent'] = 'end';
+$labels['relatedendtask'] = 'due time';
 $labels['addalarm'] = 'Add alarm';
 $labels['removealarm'] = 'Remove alarm';
 
 $labels['alarmtitle'] = 'Upcoming events';
 $labels['dismissall'] = 'Dismiss all';
 $labels['dismiss'] = 'Dismiss';
 $labels['snooze'] = 'Snooze';
 $labels['repeatinmin'] = 'Repeat in $min minutes';
 $labels['repeatinhr'] = 'Repeat in 1 hour';
 $labels['repeatinhrs'] = 'Repeat in $hrs hours';
 $labels['repeattomorrow'] = 'Repeat tomorrow';
 $labels['repeatinweek'] = 'Repeat in a week';
 
 $labels['showmore'] = 'Show more...';
 
 // recurrence related labels
 $labels['recurring'] = 'Repeats';
 $labels['frequency'] = 'Repeat';
 $labels['never'] = 'never';
 $labels['daily'] = 'daily';
 $labels['weekly'] = 'weekly';
 $labels['monthly'] = 'monthly';
 $labels['yearly'] = 'annually';
 $labels['rdate'] = 'on dates';
 $labels['every'] = 'Every';
 $labels['days'] = 'day(s)';
 $labels['weeks'] = 'week(s)';
 $labels['months'] = 'month(s)';
 $labels['years'] = 'year(s)';
 $labels['bydays'] = 'On';
 $labels['untildate'] = 'the';
 $labels['each'] = 'Each';
 $labels['onevery'] = 'On every';
 $labels['onsamedate'] = 'On the same date';
 $labels['forever'] = 'forever';
 $labels['recurrencend'] = 'until';
 $labels['untilenddate'] = 'until date';
 $labels['forntimes'] = 'for $nr time(s)';
 $labels['first'] = 'first';
 $labels['second'] = 'second';
 $labels['third'] = 'third';
 $labels['fourth'] = 'fourth';
 $labels['last'] = 'last';
 $labels['dayofmonth'] = 'Day of month';
 $labels['addrdate'] = 'Add repeat date';
 $labels['except'] = 'except';
 
 // itip related labels
 $labels['itipinvitation'] = 'Invitation to';
 $labels['itipupdate'] = 'Update of';
 $labels['itipcancellation'] = 'Cancelled:';
 $labels['itipreply'] = 'Reply to';
 $labels['itipaccepted'] = 'Accept';
 $labels['itiptentative'] = 'Maybe';
 $labels['itipdeclined'] = 'Decline';
 $labels['itipdelegated'] = 'Delegate';
 $labels['itipneeds-action'] = 'Postpone';
 $labels['itipcomment'] = 'Your response';
 $labels['itipeditresponse'] = 'Enter a response text';
 $labels['itipsendercomment'] = 'Sender\'s comment: ';
 $labels['itipsuppressreply'] = 'Do not send a response';
 
 $labels['itipobjectnotfound'] = 'The object referred by this message was not found in your account.';
 $labels['itipsubjectaccepted'] = '"$title" has been accepted by $name';
 $labels['itipsubjecttentative'] = '"$title" has been tentatively accepted by $name';
 $labels['itipsubjectdeclined'] = '"$title" has been declined by $name';
 $labels['itipsubjectin-process'] = '"$title" is in-process by $name';
 $labels['itipsubjectcompleted'] = '"$title" was completed by $name';
 $labels['itipsubjectcancel'] = 'Your participation in "$title" has been cancelled';
 $labels['itipsubjectdelegated'] = '"$title" has been delegated by $name';
 $labels['itipsubjectdelegatedto'] = '"$title" has been delegated to you by $name';
 
 $labels['itipnewattendee'] = 'This is a reply from a new participant';
 $labels['updateattendeestatus'] = 'Update the participant\'s status';
 $labels['acceptinvitation'] = 'Do you accept this invitation?';
 $labels['acceptattendee'] = 'Accept participant';
 $labels['declineattendee'] = 'Decline participant';
 $labels['declineattendeeconfirm'] = 'Enter a message to the declined participant (optional):';
 $labels['rsvpmodeall'] = 'The entire series';
 $labels['rsvpmodecurrent'] = 'This occurrence only';
 $labels['rsvpmodefuture'] = 'This and future occurrences';
 
 $labels['itipsingleoccurrence'] = 'This is a <em>single occurrence</em> out of a series of events';
 $labels['itipfutureoccurrence'] = 'Refers to <em>this and all future occurrences</em> of a series of events';
 $labels['itipmessagesingleoccurrence'] = 'The message only refers to this single occurrence';
 $labels['itipmessagefutureoccurrence'] = 'The message refers to this and all future occurrences';
 
 $labels['youhaveaccepted'] = 'You have accepted this invitation';
 $labels['youhavetentative'] = 'You have tentatively accepted this invitation';
 $labels['youhavedeclined'] = 'You have declined this invitation';
 $labels['youhavedelegated'] = 'You have delegated this invitation';
 $labels['youhavein-process'] = 'You are working on this assignment';
 $labels['youhavecompleted'] = 'You have completed this assignment';
 $labels['youhaveneeds-action'] = 'Your response to this invitation is still pending';
 
 $labels['youhavepreviouslyaccepted'] = 'You have previously accepted this invitation';
 $labels['youhavepreviouslytentative'] = 'You have previously accepted this invitation tentatively';
 $labels['youhavepreviouslydeclined'] = 'You have previously declined this invitation';
 $labels['youhavepreviouslydelegated'] = 'You have previously delegated this invitation';
 $labels['youhavepreviouslyin-process'] = 'You have previously reported to work on this assignment';
 $labels['youhavepreviouslycompleted'] = 'You have previously completed this assignment';
 $labels['youhavepreviouslyneeds-action'] = 'Your response to this invitation is still pending';
 
 $labels['attendeeaccepted'] = 'Participant has accepted';
 $labels['attendeetentative'] = 'Participant has tentatively accepted';
 $labels['attendeedeclined'] = 'Participant has declined';
 $labels['attendeedelegated'] = 'Participant has delegated to $delegatedto';
 $labels['attendeein-process'] = 'Participant is in-process';
 $labels['attendeecompleted'] = 'Participant has completed';
 $labels['notanattendee'] = 'You\'re not listed as an attendee of this object';
 $labels['outdatedinvitation'] = 'This invitation has been replaced by a newer version';
 
 $labels['importtocalendar'] = 'Save to my calendar';
 $labels['removefromcalendar'] = 'Remove from my calendar';
 $labels['updatemycopy'] = 'Update my copy';
 $labels['openpreview'] = 'Open Preview';
 
 $labels['deleteobjectconfirm'] = 'Do you really want to delete this object?';
 $labels['declinedeleteconfirm'] = 'Do you also want to delete this declined object from your account?';
 
 $labels['delegateinvitation'] = 'Delegate Invitation';
 $labels['delegateto'] = 'Delegate to';
 $labels['delegatersvpme'] = 'Keep me informed about updates of this incidence';
 $labels['delegateinvalidaddress'] = 'Please enter a valid email address for the delegate';
 
 $labels['savingdata'] = 'Saving data...';
 
 // attendees labels
 $labels['expandattendeegroup'] = 'Substitute with group members';
 $labels['expandattendeegroupnodata'] = 'Unable to substitute this group. No members found.';
 $labels['expandattendeegrouperror'] = 'Unable to substitute this group. It might contain too many members.';
 $labels['expandattendeegroupsizelimit'] = 'This group contains too many members for substituting.';
 
diff --git a/plugins/libcalendaring/tests/libcalendaring.php b/plugins/libcalendaring/tests/libcalendaring.php
index b4373ad4..311d25e2 100644
--- a/plugins/libcalendaring/tests/libcalendaring.php
+++ b/plugins/libcalendaring/tests/libcalendaring.php
@@ -1,164 +1,184 @@
 <?php
 
 /**
  * libcalendaring plugin's utility functions tests
  *
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 class libcalendaring_test extends PHPUnit_Framework_TestCase
 {
     function setUp()
     {
         require_once __DIR__ . '/../libcalendaring.php';
     }
 
     /**
      * libcalendaring::parse_alarm_value()
      */
     function test_parse_alarm_value()
     {
         $alarm = libcalendaring::parse_alarm_value('-15M');
         $this->assertEquals('15', $alarm[0]);
         $this->assertEquals('-M', $alarm[1]);
         $this->assertEquals('-PT15M', $alarm[3]);
 
         $alarm = libcalendaring::parse_alarm_value('-PT5H');
         $this->assertEquals('5',  $alarm[0]);
         $this->assertEquals('-H', $alarm[1]);
 
         $alarm = libcalendaring::parse_alarm_value('P0DT1H0M0S');
         $this->assertEquals('1',  $alarm[0]);
         $this->assertEquals('+H', $alarm[1]);
 
         // FIXME: this should return something like (1140 + 120 + 30)M
         $alarm = libcalendaring::parse_alarm_value('-P1DT2H30M');
         // $this->assertEquals('1590', $alarm[0]);
         // $this->assertEquals('-M',   $alarm[1]);
 
         $alarm = libcalendaring::parse_alarm_value('@1420722000');
         $this->assertInstanceOf('DateTime', $alarm[0]);
     }
 
     /**
      * libcalendaring::get_next_alarm()
      */
     function test_get_next_alarm()
     {
         // alarm 10 minutes before event
         $date = date('Ymd', strtotime('today + 2 days'));
         $event = array(
             'start' => new DateTime($date . 'T160000Z'),
-            'end'   => new DateTime($date . 'T180000Z'),
+            'end'   => new DateTime($date . 'T200000Z'),
             'valarms' => array(
                 array(
                     'trigger' => '-PT10M',
                     'action'  => 'DISPLAY',
                 ),
             ),
         );
         $alarm = libcalendaring::get_next_alarm($event);
         $this->assertEquals($event['valarms'][0]['action'], $alarm['action']);
         $this->assertEquals(strtotime($date . 'T155000Z'), $alarm['time']);
 
-        // alarm 1 hour after before event
+        // alarm 1 hour after event start
         $event['valarms'] = array(
             array(
                 'trigger' => '+PT1H',
             ),
         );
         $alarm = libcalendaring::get_next_alarm($event);
         $this->assertEquals('DISPLAY', $alarm['action']);
+        $this->assertEquals(strtotime($date . 'T170000Z'), $alarm['time']);
+
+        // alarm 1 hour before event end
+        $event['valarms'] = array(
+            array(
+                'trigger' => '-PT1H',
+                'related' => 'END',
+            ),
+        );
+        $alarm = libcalendaring::get_next_alarm($event);
+        $this->assertEquals('DISPLAY', $alarm['action']);
         $this->assertEquals(strtotime($date . 'T190000Z'), $alarm['time']);
 
+        // alarm 1 hour after event end
+        $event['valarms'] = array(
+            array(
+                'trigger' => 'PT1H',
+                'related' => 'END',
+            ),
+        );
+        $alarm = libcalendaring::get_next_alarm($event);
+        $this->assertEquals('DISPLAY', $alarm['action']);
+        $this->assertEquals(strtotime($date . 'T210000Z'), $alarm['time']);
+
         // ignore past alarms
         $event['start'] = new DateTime('today 22:00:00');
         $event['end']   = new DateTime('today 23:00:00');
         $event['valarms'] = array(
             array(
                 'trigger' => '-P2D',
                 'action'  => 'EMAIL',
             ),
             array(
                 'trigger' => '-PT30M',
                 'action'  => 'DISPLAY',
             ),
         );
         $alarm = libcalendaring::get_next_alarm($event);
         $this->assertEquals('DISPLAY', $alarm['action']);
         $this->assertEquals(strtotime('today 21:30:00'), $alarm['time']);
 
         // absolute alarm date/time
         $event['valarms'] = array(
             array('trigger' => new DateTime('today 20:00:00'))
         );
         $alarm = libcalendaring::get_next_alarm($event);
         $this->assertEquals($event['valarms'][0]['trigger']->format('U'), $alarm['time']);
 
         // no alarms for cancelled events
         $event['status'] = 'CANCELLED';
         $alarm = libcalendaring::get_next_alarm($event);
         $this->assertEquals(null, $alarm);
     }
 
     /**
      * libcalendaring::part_is_vcalendar()
      */
     function test_part_is_vcalendar()
     {
         $part = new StdClass;
         $part->mimetype = 'text/plain';
         $part->filename = 'event.ics';
 
         $this->assertFalse(libcalendaring::part_is_vcalendar($part));
 
         $part->mimetype = 'text/calendar';
         $this->assertTrue(libcalendaring::part_is_vcalendar($part));
 
         $part->mimetype = 'text/x-vcalendar';
         $this->assertTrue(libcalendaring::part_is_vcalendar($part));
 
         $part->mimetype = 'application/ics';
         $this->assertTrue(libcalendaring::part_is_vcalendar($part));
 
         $part->mimetype = 'application/x-any';
         $this->assertTrue(libcalendaring::part_is_vcalendar($part));
     }
 
     /**
      * libcalendaring::to_rrule()
      */
     function test_to_rrule()
     {
         $rrule = array(
             'FREQ' => 'MONTHLY',
             'BYDAY' => '2WE',
             'INTERVAL' => 2,
             'UNTIL' => new DateTime('2025-05-01 18:00:00 CEST'),
         );
 
         $s = libcalendaring::to_rrule($rrule);
 
         $this->assertRegExp('/FREQ='.$rrule['FREQ'].'/',          $s, "Recurrence Frequence");
         $this->assertRegExp('/INTERVAL='.$rrule['INTERVAL'].'/',  $s, "Recurrence Interval");
         $this->assertRegExp('/BYDAY='.$rrule['BYDAY'].'/',        $s, "Recurrence BYDAY");
         $this->assertRegExp('/UNTIL=20250501T160000Z/',           $s, "Recurrence End date (in UTC)");
     }
-
 }
-
diff --git a/plugins/libcalendaring/tests/libvcalendar.php b/plugins/libcalendaring/tests/libvcalendar.php
index ee9adb05..3d42a7a5 100644
--- a/plugins/libcalendaring/tests/libvcalendar.php
+++ b/plugins/libcalendaring/tests/libvcalendar.php
@@ -1,569 +1,571 @@
 <?php
 
 /**
  * libcalendaring plugin's iCalendar functions tests
  *
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2013, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 class libvcalendar_test extends PHPUnit_Framework_TestCase
 {
     function setUp()
     {
         require_once __DIR__ . '/../libvcalendar.php';
         require_once __DIR__ . '/../libcalendaring.php';
     }
 
     /**
      * Simple iCal parsing test
      */
     function test_import()
     {
         $ical = new libvcalendar();
         $ics = file_get_contents(__DIR__ . '/resources/snd.ics');
         $events = $ical->import($ics, 'UTF-8');
 
         $this->assertEquals(1, count($events));
         $event = $events[0];
 
         $this->assertInstanceOf('DateTime', $event['created'], "'created' property is DateTime object");
         $this->assertInstanceOf('DateTime', $event['changed'], "'changed' property is DateTime object");
         $this->assertEquals('UTC', $event['created']->getTimezone()->getName(), "'created' date is in UTC");
 
         $this->assertInstanceOf('DateTime', $event['start'], "'start' property is DateTime object");
         $this->assertInstanceOf('DateTime', $event['end'], "'end' property is DateTime object");
         $this->assertEquals('08-01', $event['start']->format('m-d'), "Start date is August 1st");
         $this->assertTrue($event['allday'], "All-day event flag");
 
         $this->assertEquals('B968B885-08FB-40E5-B89E-6DA05F26AA79', $event['uid'], "Event UID");
         $this->assertEquals('Swiss National Day', $event['title'], "Event title");
         $this->assertEquals('http://en.wikipedia.org/wiki/Swiss_National_Day', $event['url'], "URL property");
         $this->assertEquals(2, $event['sequence'], "Sequence number");
 
         $desclines = explode("\n", $event['description']);
         $this->assertEquals(4, count($desclines), "Multiline description");
         $this->assertEquals("French: Fête nationale Suisse", rtrim($desclines[1]), "UTF-8 encoding");
     }
 
     /**
      * Test parsing from files
      */
     function test_import_from_file()
     {
         $ical = new libvcalendar();
 
         $events = $ical->import_from_file(__DIR__ . '/resources/multiple.ics', 'UTF-8');
         $this->assertEquals(2, count($events));
 
         $events = $ical->import_from_file(__DIR__ . '/resources/invalid.txt', 'UTF-8');
         $this->assertEmpty($events);
     }
 
     /**
      * Test parsing from files with multiple VCALENDAR blocks (#2884)
      */
     function test_import_from_file_multiple()
     {
         $ical = new libvcalendar();
         $ical->fopen(__DIR__ . '/resources/multiple-rdate.ics', 'UTF-8');
         $events = array();
         foreach ($ical as $event) {
             $events[] = $event;
         }
 
         $this->assertEquals(2, count($events));
         $this->assertEquals("AAAA6A8C3CCE4EE2C1257B5C00FFFFFF-Lotus_Notes_Generated", $events[0]['uid']);
         $this->assertEquals("AAAA1C572093EC3FC125799C004AFFFF-Lotus_Notes_Generated", $events[1]['uid']);
     }
 
     function test_invalid_dates()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/invalid-dates.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertEquals(1, count($events), "Import event data");
         $this->assertFalse(array_key_exists('created', $event), "No created date field");
         $this->assertFalse(array_key_exists('changed', $event), "No changed date field");
     }
 
     function test_invalid_vevent()
     {
         $this->setExpectedException('\Sabre\VObject\ParseException');
 
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/invalid-event.ics', 'UTF-8', true);
     }
 
     /**
      * Test some extended ical properties such as attendees, recurrence rules, alarms and attachments
      */
     function test_extended()
     {
         $ical = new libvcalendar();
 
         $events = $ical->import_from_file(__DIR__ . '/resources/itip.ics', 'UTF-8');
         $event = $events[0];
         $this->assertEquals('REQUEST', $ical->method, "iTip method");
 
         // attendees
         $this->assertEquals(2, count($event['attendees']), "Attendees list (including organizer)");
         $organizer = $event['attendees'][0];
         $this->assertEquals('ORGANIZER', $organizer['role'], 'Organizer ROLE');
         $this->assertEquals('Rolf Test', $organizer['name'], 'Organizer name');
 
         $attendee = $event['attendees'][1];
         $this->assertEquals('REQ-PARTICIPANT', $attendee['role'], 'Attendee ROLE');
         $this->assertEquals('NEEDS-ACTION', $attendee['status'], 'Attendee STATUS');
         $this->assertEquals('rolf2@mykolab.com', $attendee['email'], 'Attendee mailto:');
         $this->assertTrue($attendee['rsvp'], 'Attendee RSVP');
 
         // attachments
         $this->assertEquals(1, count($event['attachments']), "Embedded attachments");
         $attachment = $event['attachments'][0];
         $this->assertEquals('text/html',                 $attachment['mimetype'], "Attachment mimetype attribute");
         $this->assertEquals('calendar.html',             $attachment['name'],     "Attachment filename (X-LABEL) attribute");
         $this->assertContains('<title>Kalender</title>', $attachment['data'],     "Attachment content (decoded)");
 
         // recurrence rules
         $events = $ical->import_from_file(__DIR__ . '/resources/recurring.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertTrue(is_array($event['recurrence']), 'Recurrences rule as hash array');
         $rrule = $event['recurrence'];
         $this->assertEquals('MONTHLY',      $rrule['FREQ'],     "Recurrence frequency");
         $this->assertEquals('1',            $rrule['INTERVAL'], "Recurrence interval");
         $this->assertEquals('3WE',          $rrule['BYDAY'],    "Recurrence frequency");
         $this->assertInstanceOf('DateTime', $rrule['UNTIL'],    "Recurrence end date");
 
         $this->assertEquals(2, count($rrule['EXDATE']),          "Recurrence EXDATEs");
         $this->assertInstanceOf('DateTime', $rrule['EXDATE'][0], "Recurrence EXDATE as DateTime");
 
         // categories, class
         $this->assertEquals('libcalendaring tests', join(',', (array)$event['categories']), "Event categories");
         $this->assertEquals('confidential', $event['sensitivity'], "Class/sensitivity = confidential");
 
         // parse a recurrence chain instance
         $events = $ical->import_from_file(__DIR__ . '/resources/recurrence-id.ics', 'UTF-8');
         $this->assertEquals(1, count($events), "Fall back to Component::getComponents() when getBaseComponents() is empty");
         $this->assertInstanceOf('DateTime', $events[0]['recurrence_date'], "Recurrence-ID as date");
         $this->assertTrue($events[0]['thisandfuture'], "Range=THISANDFUTURE");
 
         $this->assertEquals(count($events[0]['exceptions']), 1, "Second VEVENT as exception");
         $this->assertEquals($events[0]['exceptions'][0]['uid'], $events[0]['uid'], "Exception UID match");
         $this->assertEquals($events[0]['exceptions'][0]['sequence'], '2', "Exception sequence");
     }
 
     /**
      * 
      */
     function test_alarms()
     {
         $ical = new libvcalendar();
 
         $events = $ical->import_from_file(__DIR__ . '/resources/recurring.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertEquals('-12H:DISPLAY', $event['alarms'], "Serialized alarms string");
         $alarm = libcalendaring::parse_alarm_value($event['alarms']);
         $this->assertEquals('12', $alarm[0], "Alarm value");
         $this->assertEquals('-H', $alarm[1], "Alarm unit");
 
         $this->assertEquals('DISPLAY', $event['valarms'][0]['action'],  "Full alarm item (action)");
         $this->assertEquals('-PT12H',  $event['valarms'][0]['trigger'], "Full alarm item (trigger)");
+        $this->assertEquals('END',  $event['valarms'][0]['related'], "Full alarm item (related)");
 
         // alarm trigger with 0 values
         $events = $ical->import_from_file(__DIR__ . '/resources/alarms.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertEquals('-30M:DISPLAY', $event['alarms'], "Stripped alarm string");
         $alarm = libcalendaring::parse_alarm_value($event['alarms']);
         $this->assertEquals('30', $alarm[0], "Alarm value");
         $this->assertEquals('-M', $alarm[1], "Alarm unit");
         $this->assertEquals('-30M', $alarm[2], "Alarm string");
         $this->assertEquals('-PT30M', $alarm[3], "Unified alarm string (stripped zero-values)");
 
         $this->assertEquals('DISPLAY', $event['valarms'][0]['action'],  "First alarm action");
+        $this->assertEquals('', $event['valarms'][0]['related'],  "First alarm related property");
         $this->assertEquals('This is the first event reminder', $event['valarms'][0]['description'],  "First alarm text");
 
         $this->assertEquals(2, count($event['valarms']), "List all VALARM blocks");
 
         $valarm = $event['valarms'][1];
         $this->assertEquals(1, count($valarm['attendees']), "Email alarm attendees");
         $this->assertEquals('EMAIL', $valarm['action'],  "Second alarm item (action)");
         $this->assertEquals('-P1D',  $valarm['trigger'], "Second alarm item (trigger)");
         $this->assertEquals('This is the reminder message',  $valarm['summary'], "Email alarm text");
 
         // test alarms export
         $ics = $ical->export(array($event));
         $this->assertContains('ACTION:DISPLAY',   $ics, "Display alarm block");
         $this->assertContains('ACTION:EMAIL',     $ics, "Email alarm block");
         $this->assertContains('DESCRIPTION:This is the first event reminder',    $ics, "Alarm description");
         $this->assertContains('SUMMARY:This is the reminder message',            $ics, "Email alarm summary");
         $this->assertContains('ATTENDEE:mailto:reminder-recipient@example.org',  $ics, "Email alarm recipient");
     }
 
     /**
      * @depends test_import_from_file
      */
     function test_attachment()
     {
         $ical = new libvcalendar();
 
         $events = $ical->import_from_file(__DIR__ . '/resources/attachment.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertEquals(2, count($events));
         $this->assertEquals(1, count($event['attachments']));
         $this->assertEquals('image/png', $event['attachments'][0]['mimetype']);
         $this->assertEquals('500px-Opensource.svg.png', $event['attachments'][0]['name']);
     }
 
     /**
      * @depends test_import
      */
     function test_apple_alarms()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/apple-alarms.ics', 'UTF-8');
         $event = $events[0];
 
         // alarms
         $this->assertEquals('-45M:AUDIO', $event['alarms'], "Relative alarm string");
         $alarm = libcalendaring::parse_alarm_value($event['alarms']);
         $this->assertEquals('45', $alarm[0], "Alarm value");
         $this->assertEquals('-M', $alarm[1], "Alarm unit");
 
         $this->assertEquals(1, count($event['valarms']), "Ignore invalid alarm blocks");
         $this->assertEquals('AUDIO', $event['valarms'][0]['action'],   "Full alarm item (action)");
         $this->assertEquals('-PT45M', $event['valarms'][0]['trigger'], "Full alarm item (trigger)");
         $this->assertEquals('Basso',  $event['valarms'][0]['uri'],     "Full alarm item (attachment)");
     }
 
     /**
      * 
      */
     function test_escaped_values()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/escaped.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertEquals("House, Street, Zip Place", $event['location'], "Decode escaped commas in location value");
         $this->assertEquals("Me, meets Them\nThem, meet Me", $event['description'], "Decode description value");
         $this->assertEquals("Kolab, Thomas", $event['attendees'][3]['name'], "Unescaped");
 
         $ics = $ical->export($events);
         $this->assertContains('ATTENDEE;CN="Kolab, Thomas";PARTSTAT=', $ics, "Quoted attendee parameters");
     }
 
     /**
      * Parse RDATE properties (#2885)
      */
     function test_rdate()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/multiple-rdate.ics', 'UTF-8');
         $event = $events[0];
 
         $this->assertEquals(9, count($event['recurrence']['RDATE']));
         $this->assertInstanceOf('DateTime', $event['recurrence']['RDATE'][0]);
     }
 
     /**
      * @depends test_import
      */
     function test_freebusy()
     {
         $ical = new libvcalendar();
         $ical->import_from_file(__DIR__ . '/resources/freebusy.ifb', 'UTF-8');
         $freebusy = $ical->freebusy;
 
         $this->assertInstanceOf('DateTime', $freebusy['start'], "'start' property is DateTime object");
         $this->assertInstanceOf('DateTime', $freebusy['end'], "'end' property is DateTime object");
         $this->assertEquals(11, count($freebusy['periods']), "Number of freebusy periods defined");
         $this->assertEquals(9, count($ical->get_busy_periods()), "Number of busy periods found");
     }
 
     /**
      * @depends test_import
      */
     function test_freebusy_dummy()
     {
         $ical = new libvcalendar();
         $ical->import_from_file(__DIR__ . '/resources/dummy.ifb', 'UTF-8');
         $freebusy = $ical->freebusy;
 
         $this->assertEquals(0, count($freebusy['periods']), "Ignore 0-length freebudy periods");
         $this->assertContains('dummy', $freebusy['comment'], "Parse comment");
     }
 
     function test_vtodo()
     {
         $ical = new libvcalendar();
         $tasks = $ical->import_from_file(__DIR__ . '/resources/vtodo.ics', 'UTF-8', true);
         $task = $tasks[0];
 
         $this->assertInstanceOf('DateTime', $task['start'],   "'start' property is DateTime object");
         $this->assertInstanceOf('DateTime', $task['due'],     "'due' property is DateTime object");
         $this->assertEquals('-1D:DISPLAY',  $task['alarms'],  "Taks alarm value");
         $this->assertEquals('IN-PROCESS',   $task['status'],  "Task status property");
         $this->assertEquals(1, count($task['x-custom']),      "Custom properties");
         $this->assertEquals(4, count($task['categories']));
         $this->assertEquals('1234567890-12345678-PARENT', $task['parent_id'], "Parent Relation");
 
         $completed = $tasks[1];
         $this->assertEquals('COMPLETED', $completed['status'], "Task status=completed when COMPLETED property is present");
         $this->assertEquals(100, $completed['complete'], "Task percent complete value");
 
         $ics = $ical->export(array($completed));
-        $this->assertRegExp('/COMPLETED:[0-9TZ]+/', $ics, "Export COMPLETED property");
+        $this->assertRegExp('/COMPLETED(;VALUE=DATE-TIME)?:[0-9TZ]+/', $ics, "Export COMPLETED property");
     }
 
     /**
      * Test for iCal export from internal hash array representation
      *
      * 
      */
     function test_export()
     {
         $ical = new libvcalendar();
 
         $events = $ical->import_from_file(__DIR__ . '/resources/itip.ics', 'UTF-8');
         $event = $events[0];
         $events = $ical->import_from_file(__DIR__ . '/resources/recurring.ics', 'UTF-8');
         $event += $events[0];
 
         $this->attachment_data = $event['attachments'][0]['data'];
         unset($event['attachments'][0]['data']);
         $event['attachments'][0]['id'] = '1';
         $event['description'] = '*Exported by libvcalendar*';
 
         $event['start']->setTimezone(new DateTimezone('Europe/Berlin'));
         $event['end']->setTimezone(new DateTimezone('Europe/Berlin'));
 
         $ics = $ical->export(array($event), 'REQUEST', false, array($this, 'get_attachment_data'), true);
 
         $this->assertContains('BEGIN:VCALENDAR',    $ics, "VCALENDAR encapsulation BEGIN");
 
         $this->assertContains('BEGIN:VTIMEZONE', $ics, "VTIMEZONE encapsulation BEGIN");
         $this->assertContains('TZID:Europe/Berlin', $ics, "Timezone ID");
         $this->assertContains('TZOFFSETFROM:+0100', $ics, "Timzone transition FROM");
         $this->assertContains('TZOFFSETTO:+0200', $ics, "Timzone transition TO");
         $this->assertContains('END:VTIMEZONE', $ics, "VTIMEZONE encapsulation END");
 
         $this->assertContains('BEGIN:VEVENT',       $ics, "VEVENT encapsulation BEGIN");
         $this->assertContains('UID:ac6b0aee-2519-4e5c-9a25-48c57064c9f0', $ics, "Event UID");
         $this->assertContains('SEQUENCE:' . $event['sequence'],           $ics, "Export Sequence number");
         $this->assertContains('CLASS:CONFIDENTIAL',                       $ics, "Sensitivity => Class");
         $this->assertContains('DESCRIPTION:*Exported by',                 $ics, "Export Description");
         $this->assertContains('ORGANIZER;CN=Rolf Test:mailto:rolf@',    $ics, "Export organizer");
         $this->assertRegExp('/ATTENDEE.*;ROLE=REQ-PARTICIPANT/',          $ics, "Export Attendee ROLE");
         $this->assertRegExp('/ATTENDEE.*;PARTSTAT=NEEDS-ACTION/',         $ics, "Export Attendee Status");
         $this->assertRegExp('/ATTENDEE.*;RSVP=TRUE/',                     $ics, "Export Attendee RSVP");
         $this->assertRegExp('/ATTENDEE.*:mailto:rolf2@/',                 $ics, "Export Attendee mailto:");
 
         $rrule = $event['recurrence'];
         $this->assertRegExp('/RRULE:.*FREQ='.$rrule['FREQ'].'/',          $ics, "Export Recurrence Frequence");
         $this->assertRegExp('/RRULE:.*INTERVAL='.$rrule['INTERVAL'].'/',  $ics, "Export Recurrence Interval");
         $this->assertRegExp('/RRULE:.*UNTIL=20140718T215959Z/',           $ics, "Export Recurrence End date");
         $this->assertRegExp('/RRULE:.*BYDAY='.$rrule['BYDAY'].'/',        $ics, "Export Recurrence BYDAY");
         $this->assertRegExp('/EXDATE.*:20131218/',     $ics, "Export Recurrence EXDATE");
 
         $this->assertContains('BEGIN:VALARM',   $ics, "Export VALARM");
-        $this->assertContains('TRIGGER:-PT12H', $ics, "Export Alarm trigger");
+        $this->assertContains('TRIGGER;RELATED=END:-PT12H', $ics, "Export Alarm trigger");
 
         $this->assertRegExp('/ATTACH.*;VALUE=BINARY/',                    $ics, "Embed attachment");
         $this->assertRegExp('/ATTACH.*;ENCODING=BASE64/',                 $ics, "Attachment B64 encoding");
         $this->assertRegExp('!ATTACH.*;FMTTYPE=text/html!',               $ics, "Attachment mimetype");
         $this->assertRegExp('!ATTACH.*;X-LABEL=calendar.html!',           $ics, "Attachment filename with X-LABEL");
 
         $this->assertContains('END:VEVENT',     $ics, "VEVENT encapsulation END");
         $this->assertContains('END:VCALENDAR',  $ics, "VCALENDAR encapsulation END");
     }
 
     /**
      * @depends test_extended
      * @depends test_export
      */
     function test_export_multiple()
     {
         $ical = new libvcalendar();
         $events = array_merge(
             $ical->import_from_file(__DIR__ . '/resources/snd.ics', 'UTF-8'),
             $ical->import_from_file(__DIR__ . '/resources/multiple.ics', 'UTF-8')
         );
 
         $num = count($events);
         $ics = $ical->export($events, null, false);
 
         $this->assertContains('BEGIN:VCALENDAR', $ics, "VCALENDAR encapsulation BEGIN");
         $this->assertContains('END:VCALENDAR',   $ics, "VCALENDAR encapsulation END");
         $this->assertEquals($num, substr_count($ics, 'BEGIN:VEVENT'), "VEVENT encapsulation BEGIN");
         $this->assertEquals($num, substr_count($ics, 'END:VEVENT'),   "VEVENT encapsulation END");
     }
 
     /**
      * @depends test_export
      */
     function test_export_recurrence_exceptions()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/recurring.ics', 'UTF-8');
 
         // add exceptions
         $event = $events[0];
         $exception1 = $event;
         $exception1['start'] = clone $event['start'];
         $exception1['start']->setDate(2013, 8, 14);
         $exception1['end'] = clone $event['end'];
         $exception1['end']->setDate(2013, 8, 14);
 
         $exception2 = $event;
         $exception2['start'] = clone $event['start'];
         $exception2['start']->setDate(2013, 11, 13);
         $exception2['end'] = clone $event['end'];
         $exception2['end']->setDate(2013, 11, 13);
         $exception2['title'] = 'Recurring Exception';
 
         $events[0]['recurrence']['EXCEPTIONS'] = array($exception1, $exception2);
 
         $ics = $ical->export($events, null, false);
 
         $num = count($events[0]['recurrence']['EXCEPTIONS']) + 1;
         $this->assertEquals($num, substr_count($ics, 'BEGIN:VEVENT'),       "VEVENT encapsulation BEGIN");
         $this->assertEquals($num, substr_count($ics, 'UID:'.$event['uid']), "Recurrence Exceptions with same UID");
         $this->assertEquals($num, substr_count($ics, 'END:VEVENT'),         "VEVENT encapsulation END");
 
         $this->assertContains('RECURRENCE-ID;VALUE=DATE-TIME;TZID=Europe/Zurich:20130814', $ics, "Recurrence-ID (1) being the exception date");
         $this->assertContains('RECURRENCE-ID;VALUE=DATE-TIME;TZID=Europe/Zurich:20131113', $ics, "Recurrence-ID (2) being the exception date");
         $this->assertContains('SUMMARY:'.$exception2['title'], $ics, "Exception title");
     }
 
     function test_export_valid_rrules()
     {
         $event = array(
             'uid' => '1234567890',
             'start' => new DateTime('now'),
             'end' => new DateTime('now + 30min'),
             'title' => 'test_export_valid_rrules',
             'recurrence' => array(
                 'FREQ' => 'DAILY',
                 'COUNT' => 5,
                 'EXDATE' => array(),
                 'RDATE' => array(),
             ),
         );
         $ical = new libvcalendar();
         $ics = $ical->export(array($event), null, false, null, false);
 
         $this->assertNotContains('EXDATE=', $ics);
         $this->assertNotContains('RDATE=', $ics);
     }
 
     /**
      *
      */
     function test_export_rdate()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/multiple-rdate.ics', 'UTF-8');
         $ics = $ical->export($events, null, false);
 
         $this->assertContains('RDATE;VALUE=DATE-TIME:20140520T020000Z', $ics, "VALUE=PERIOD is translated into single DATE-TIME values");
     }
 
     /**
      * @depends test_export
      */
     function test_export_direct()
     {
         $ical = new libvcalendar();
         $events = $ical->import_from_file(__DIR__ . '/resources/multiple.ics', 'UTF-8');
         $num = count($events);
 
         ob_start();
         $return = $ical->export($events, null, true);
         $output = ob_get_contents();
         ob_end_clean();
 
         $this->assertTrue($return, "Return true on successful writing");
         $this->assertContains('BEGIN:VCALENDAR', $output, "VCALENDAR encapsulation BEGIN");
         $this->assertContains('END:VCALENDAR',   $output, "VCALENDAR encapsulation END");
         $this->assertEquals($num, substr_count($output, 'BEGIN:VEVENT'), "VEVENT encapsulation BEGIN");
         $this->assertEquals($num, substr_count($output, 'END:VEVENT'),   "VEVENT encapsulation END");
     }
 
     function test_datetime()
     {
         $ical = new libvcalendar();
         $localtime = $ical->datetime_prop('DTSTART', new DateTime('2013-09-01 12:00:00', new DateTimeZone('Europe/Berlin')));
         $localdate = $ical->datetime_prop('DTSTART', new DateTime('2013-09-01', new DateTimeZone('Europe/Berlin')), false, true);
         $utctime   = $ical->datetime_prop('DTSTART', new DateTime('2013-09-01 12:00:00', new DateTimeZone('UTC')));
         $asutctime = $ical->datetime_prop('DTSTART', new DateTime('2013-09-01 12:00:00', new DateTimeZone('Europe/Berlin')), true);
 
         $this->assertContains('TZID=Europe/Berlin', $localtime->serialize());
         $this->assertContains('VALUE=DATE', $localdate->serialize());
         $this->assertContains('20130901T120000Z', $utctime->serialize());
         $this->assertContains('20130901T100000Z', $asutctime->serialize());
     }
 
     function test_get_vtimezone()
     {
         $vtz = libvcalendar::get_vtimezone('Europe/Berlin', strtotime('2014-08-22T15:00:00+02:00'));
         $this->assertInstanceOf('\Sabre\VObject\Component', $vtz, "VTIMEZONE is a Component object");
         $this->assertEquals('Europe/Berlin', $vtz->TZID);
         $this->assertEquals('4', $vtz->{'X-MICROSOFT-CDO-TZID'});
 
         // check for transition to daylight saving time which is BEFORE the given date
         $dst = reset($vtz->select('DAYLIGHT'));
         $this->assertEquals('DAYLIGHT', $dst->name);
         $this->assertEquals('20140330T010000', $dst->DTSTART);
         $this->assertEquals('+0100', $dst->TZOFFSETFROM);
         $this->assertEquals('+0200', $dst->TZOFFSETTO);
         $this->assertEquals('CEST', $dst->TZNAME);
 
         // check (last) transition to standard time which is AFTER the given date
         $std = end($vtz->select('STANDARD'));
         $this->assertEquals('STANDARD', $std->name);
         $this->assertEquals('20141026T010000', $std->DTSTART);
         $this->assertEquals('+0200', $std->TZOFFSETFROM);
         $this->assertEquals('+0100', $std->TZOFFSETTO);
         $this->assertEquals('CET', $std->TZNAME);
 
         // unknown timezone
         $vtz = libvcalendar::get_vtimezone('America/Foo Bar');
         $this->assertEquals(false, $vtz);
 
         // invalid input data
         $vtz = libvcalendar::get_vtimezone(new DateTime());
         $this->assertEquals(false, $vtz);
 
         // DateTimezone as input data
         $vtz = libvcalendar::get_vtimezone(new DateTimezone('Pacific/Chatham'));
         $this->assertInstanceOf('\Sabre\VObject\Component', $vtz);
         $this->assertContains('TZOFFSETFROM:+1245', $vtz->serialize());
         $this->assertContains('TZOFFSETTO:+1345', $vtz->serialize());
     }
 
     function get_attachment_data($id, $event)
     {
         return $this->attachment_data;
     }
 }
 
diff --git a/plugins/libcalendaring/tests/resources/recurring.ics b/plugins/libcalendaring/tests/resources/recurring.ics
index 92db9e28..8fed3878 100644
--- a/plugins/libcalendaring/tests/resources/recurring.ics
+++ b/plugins/libcalendaring/tests/resources/recurring.ics
@@ -1,43 +1,43 @@
 BEGIN:VCALENDAR
 VERSION:2.0
 PRODID:-//Apple Inc.//iCal 5.0.3//EN
 CALSCALE:GREGORIAN
 BEGIN:VTIMEZONE
 TZID:Europe/Zurich
 BEGIN:DAYLIGHT
 TZOFFSETFROM:+0100
 RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
 DTSTART:19810329T020000
 TZNAME:CEST
 TZOFFSETTO:+0200
 END:DAYLIGHT
 BEGIN:STANDARD
 TZOFFSETFROM:+0200
 RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
 DTSTART:19961027T030000
 TZNAME:CET
 TZOFFSETTO:+0100
 END:STANDARD
 END:VTIMEZONE
 BEGIN:VEVENT
 PRIORITY:3
 DTEND;TZID=Europe/Zurich:20130717T130000
 TRANSP:TRANSPARENT
 UID:7e93e8e8eef16f28aa33b78cd73613eb
 DTSTAMP:20130718T082032Z
 SEQUENCE:6
 CLASS:CONFIDENTIAL
 CATEGORIES:libcalendaring tests
 SUMMARY:Recurring Test
 LAST-MODIFIED:20120621
 DTSTART;TZID=Europe/Zurich:20130717T080000
 CREATED:20081223T232600Z
 RRULE:FREQ=MONTHLY;INTERVAL=1;UNTIL=20140718T215959Z;BYDAY=3WE
 EXDATE;TZID=Europe/Zurich:20131218T080000
 EXDATE;TZID=Europe/Zurich:20140415T080000
 BEGIN:VALARM
-TRIGGER:-PT12H
+TRIGGER;RELATED=END:-PT12H
 ACTION:DISPLAY
 END:VALARM
 END:VEVENT
 END:VCALENDAR
diff --git a/plugins/libkolab/lib/kolab_format_xcal.php b/plugins/libkolab/lib/kolab_format_xcal.php
index e7d1122a..a9dd70c8 100644
--- a/plugins/libkolab/lib/kolab_format_xcal.php
+++ b/plugins/libkolab/lib/kolab_format_xcal.php
@@ -1,706 +1,714 @@
 <?php
 
 /**
  * Xcal based Kolab format class wrapping libkolabxml bindings
  *
  * Base class for xcal-based Kolab groupware objects such as event, todo, journal
  *
  * @version @package_version@
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2012, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 abstract class kolab_format_xcal extends kolab_format
 {
     public $CTYPE = 'application/calendar+xml';
 
     public static $fulltext_cols = array('title', 'description', 'location', 'attendees:name', 'attendees:email', 'categories');
 
     public static $scheduling_properties = array('start', 'end', 'location');
 
     protected $_scheduling_properties = null;
 
     protected $sensitivity_map = array(
         'public'       => kolabformat::ClassPublic,
         'private'      => kolabformat::ClassPrivate,
         'confidential' => kolabformat::ClassConfidential,
     );
 
     protected $role_map = array(
         'REQ-PARTICIPANT' => kolabformat::Required,
         'OPT-PARTICIPANT' => kolabformat::Optional,
         'NON-PARTICIPANT' => kolabformat::NonParticipant,
         'CHAIR' => kolabformat::Chair,
     );
 
     protected $cutype_map = array(
         'INDIVIDUAL' => kolabformat::CutypeIndividual,
         'GROUP'      => kolabformat::CutypeGroup,
         'ROOM'       => kolabformat::CutypeRoom,
         'RESOURCE'   => kolabformat::CutypeResource,
         'UNKNOWN'    => kolabformat::CutypeUnknown,
     );
 
     protected $rrule_type_map = array(
         'MINUTELY' => RecurrenceRule::Minutely,
         'HOURLY' => RecurrenceRule::Hourly,
         'DAILY' => RecurrenceRule::Daily,
         'WEEKLY' => RecurrenceRule::Weekly,
         'MONTHLY' => RecurrenceRule::Monthly,
         'YEARLY' => RecurrenceRule::Yearly,
     );
 
     protected $weekday_map = array(
         'MO' => kolabformat::Monday,
         'TU' => kolabformat::Tuesday,
         'WE' => kolabformat::Wednesday,
         'TH' => kolabformat::Thursday,
         'FR' => kolabformat::Friday,
         'SA' => kolabformat::Saturday,
         'SU' => kolabformat::Sunday,
     );
 
     protected $alarm_type_map = array(
         'DISPLAY' => Alarm::DisplayAlarm,
         'EMAIL' => Alarm::EMailAlarm,
         'AUDIO' => Alarm::AudioAlarm,
     );
 
     protected $status_map = array(
         'NEEDS-ACTION' => kolabformat::StatusNeedsAction,
         'IN-PROCESS'   => kolabformat::StatusInProcess,
         'COMPLETED'    => kolabformat::StatusCompleted,
         'CANCELLED'    => kolabformat::StatusCancelled,
         'TENTATIVE'    => kolabformat::StatusTentative,
         'CONFIRMED'    => kolabformat::StatusConfirmed,
         'DRAFT'        => kolabformat::StatusDraft,
         'FINAL'        => kolabformat::StatusFinal,
     );
 
     protected $part_status_map = array(
         'UNKNOWN' => kolabformat::PartNeedsAction,
         'NEEDS-ACTION' => kolabformat::PartNeedsAction,
         'TENTATIVE' => kolabformat::PartTentative,
         'ACCEPTED' => kolabformat::PartAccepted,
         'DECLINED' => kolabformat::PartDeclined,
         'DELEGATED' => kolabformat::PartDelegated,
       );
 
 
     /**
      * Convert common xcard properties into a hash array data structure
      *
      * @param array Additional data for merge
      *
      * @return array  Object data as hash array
      */
     public function to_array($data = array())
     {
         // read common object props
         $object = parent::to_array($data);
 
         $status_map = array_flip($this->status_map);
         $sensitivity_map = array_flip($this->sensitivity_map);
 
         $object += array(
             'sequence'    => intval($this->obj->sequence()),
             'title'       => $this->obj->summary(),
             'location'    => $this->obj->location(),
             'description' => $this->obj->description(),
             'url'         => $this->obj->url(),
             'status'      => $status_map[$this->obj->status()],
             'sensitivity' => $sensitivity_map[$this->obj->classification()],
             'priority'    => $this->obj->priority(),
             'categories'  => self::vector2array($this->obj->categories()),
             'start'       => self::php_datetime($this->obj->start()),
         );
 
         if (method_exists($this->obj, 'comment')) {
             $object['comment'] = $this->obj->comment();
         }
 
         // read organizer and attendees
         if (($organizer = $this->obj->organizer()) && ($organizer->email() || $organizer->name())) {
             $object['organizer'] = array(
                 'email' => $organizer->email(),
                 'name' => $organizer->name(),
             );
         }
 
         $role_map = array_flip($this->role_map);
         $cutype_map = array_flip($this->cutype_map);
         $part_status_map = array_flip($this->part_status_map);
         $attvec = $this->obj->attendees();
         for ($i=0; $i < $attvec->size(); $i++) {
             $attendee = $attvec->get($i);
             $cr = $attendee->contact();
             if ($cr->email() != $object['organizer']['email']) {
                 $delegators = $delegatees = array();
                 $vdelegators = $attendee->delegatedFrom();
                 for ($j=0; $j < $vdelegators->size(); $j++) {
                     $delegators[] = $vdelegators->get($j)->email();
                 }
                 $vdelegatees = $attendee->delegatedTo();
                 for ($j=0; $j < $vdelegatees->size(); $j++) {
                     $delegatees[] = $vdelegatees->get($j)->email();
                 }
 
                 $object['attendees'][] = array(
                     'role' => $role_map[$attendee->role()],
                     'cutype' => $cutype_map[$attendee->cutype()],
                     'status' => $part_status_map[$attendee->partStat()],
                     'rsvp' => $attendee->rsvp(),
                     'email' => $cr->email(),
                     'name' => $cr->name(),
                     'delegated-from' => $delegators,
                     'delegated-to' => $delegatees,
                 );
             }
         }
 
         // read recurrence rule
         if (($rr = $this->obj->recurrenceRule()) && $rr->isValid()) {
             $rrule_type_map = array_flip($this->rrule_type_map);
             $object['recurrence'] = array('FREQ' => $rrule_type_map[$rr->frequency()]);
 
             if ($intvl = $rr->interval())
                 $object['recurrence']['INTERVAL'] = $intvl;
 
             if (($count = $rr->count()) && $count > 0) {
                 $object['recurrence']['COUNT'] = $count;
             }
             else if ($until = self::php_datetime($rr->end())) {
                 $refdate = $this->get_reference_date();
                 if ($refdate && $refdate instanceof DateTime && !$refdate->_dateonly) {
                     $until->setTime($refdate->format('G'), $refdate->format('i'), 0);
                 }
                 $object['recurrence']['UNTIL'] = $until;
             }
 
             if (($byday = $rr->byday()) && $byday->size()) {
                 $weekday_map = array_flip($this->weekday_map);
                 $weekdays = array();
                 for ($i=0; $i < $byday->size(); $i++) {
                     $daypos = $byday->get($i);
                     $prefix = $daypos->occurence();
                     $weekdays[] = ($prefix ? $prefix : '') . $weekday_map[$daypos->weekday()];
                 }
                 $object['recurrence']['BYDAY'] = join(',', $weekdays);
             }
 
             if (($bymday = $rr->bymonthday()) && $bymday->size()) {
                 $object['recurrence']['BYMONTHDAY'] = join(',', self::vector2array($bymday));
             }
 
             if (($bymonth = $rr->bymonth()) && $bymonth->size()) {
                 $object['recurrence']['BYMONTH'] = join(',', self::vector2array($bymonth));
             }
 
             if ($exdates = $this->obj->exceptionDates()) {
                 for ($i=0; $i < $exdates->size(); $i++) {
                     if ($exdate = self::php_datetime($exdates->get($i)))
                         $object['recurrence']['EXDATE'][] = $exdate;
                 }
             }
         }
 
         if ($rdates = $this->obj->recurrenceDates()) {
             for ($i=0; $i < $rdates->size(); $i++) {
                 if ($rdate = self::php_datetime($rdates->get($i)))
                     $object['recurrence']['RDATE'][] = $rdate;
             }
         }
 
         // read alarm
         $valarms = $this->obj->alarms();
         $alarm_types = array_flip($this->alarm_type_map);
         $object['valarms'] = array();
         for ($i=0; $i < $valarms->size(); $i++) {
             $alarm = $valarms->get($i);
-            $type = $alarm_types[$alarm->type()];
+            $type  = $alarm_types[$alarm->type()];
 
             if ($type == 'DISPLAY' || $type == 'EMAIL' || $type == 'AUDIO') {  // only some alarms are supported
                 $valarm = array(
-                    'action' => $type,
-                    'summary' => $alarm->summary(),
+                    'action'      => $type,
+                    'summary'     => $alarm->summary(),
                     'description' => $alarm->description(),
                 );
 
                 if ($type == 'EMAIL') {
                     $valarm['attendees'] = array();
                     $attvec = $alarm->attendees();
                     for ($j=0; $j < $attvec->size(); $j++) {
                         $cr = $attvec->get($j);
                         $valarm['attendees'][] = $cr->email();
                     }
                 }
                 else if ($type == 'AUDIO') {
                     $attach = $alarm->audioFile();
                     $valarm['uri'] = $attach->uri();
                 }
 
                 if ($start = self::php_datetime($alarm->start())) {
-                    $object['alarms'] = '@' . $start->format('U');
+                    $object['alarms']  = '@' . $start->format('U');
                     $valarm['trigger'] = $start;
                 }
                 else if ($offset = $alarm->relativeStart()) {
-                    $prefix = $alarm->relativeTo() == kolabformat::End ? '+' : '-';
-                    $value = $time = '';
+                    $prefix = $offset->isNegative() ? '-' : '+';
+                    $value  = '';
+                    $time   = '';
+
                     if      ($w = $offset->weeks())     $value .= $w . 'W';
                     else if ($d = $offset->days())      $value .= $d . 'D';
                     else if ($h = $offset->hours())     $time  .= $h . 'H';
                     else if ($m = $offset->minutes())   $time  .= $m . 'M';
                     else if ($s = $offset->seconds())   $time  .= $s . 'S';
 
                     // assume 'at event time'
                     if (empty($value) && empty($time)) {
                         $prefix = '';
-                        $time = '0S';
+                        $time   = '0S';
                     }
 
-                    $object['alarms'] = $prefix . $value . $time;
+                    $object['alarms']  = $prefix . $value . $time;
                     $valarm['trigger'] = $prefix . 'P' . $value . ($time ? 'T' . $time : '');
+
+                    if ($alarm->relativeTo() == kolabformat::End) {
+                        $valarm['related'] == 'END';
+                    }
                 }
 
                 // read alarm duration and repeat properties
                 if (($duration = $alarm->duration()) && $duration->isValid()) {
                     $value = $time = '';
+
                     if      ($w = $duration->weeks())     $value .= $w . 'W';
                     else if ($d = $duration->days())      $value .= $d . 'D';
                     else if ($h = $duration->hours())     $time  .= $h . 'H';
                     else if ($m = $duration->minutes())   $time  .= $m . 'M';
                     else if ($s = $duration->seconds())   $time  .= $s . 'S';
+
                     $valarm['duration'] = 'P' . $value . ($time ? 'T' . $time : '');
-                    $valarm['repeat'] = $alarm->numrepeat();
+                    $valarm['repeat']   = $alarm->numrepeat();
                 }
 
                 $object['alarms']  .= ':' . $type;  // legacy property
                 $object['valarms'][] = array_filter($valarm);
             }
         }
 
         $this->get_attachments($object);
 
         return $object;
     }
 
 
     /**
      * Set common xcal properties to the kolabformat object
      *
      * @param array  Event data as hash array
      */
     public function set(&$object)
     {
         $this->init();
 
         $is_new = !$this->obj->uid();
         $old_sequence = $this->obj->sequence();
         $reschedule = $is_new;
 
         // set common object properties
         parent::set($object);
 
         // set sequence value
         if (!isset($object['sequence'])) {
             if ($is_new) {
                 $object['sequence'] = 0;
             }
             else {
                 $object['sequence'] = $old_sequence;
 
                 // increment sequence when updating properties relevant for scheduling.
                 // RFC 5545: "It is incremented [...] each time the Organizer makes a significant revision to the calendar component."
                 if ($this->check_rescheduling($object)) {
                     $object['sequence']++;
                 }
             }
         }
         $this->obj->setSequence(intval($object['sequence']));
 
         if ($object['sequence'] > $old_sequence) {
             $reschedule = true;
         }
 
         $this->obj->setSummary($object['title']);
         $this->obj->setLocation($object['location']);
         $this->obj->setDescription($object['description']);
         $this->obj->setPriority($object['priority']);
         $this->obj->setClassification($this->sensitivity_map[$object['sensitivity']]);
         $this->obj->setCategories(self::array2vector($object['categories']));
         $this->obj->setUrl(strval($object['url']));
 
         if (method_exists($this->obj, 'setComment')) {
             $this->obj->setComment($object['comment']);
         }
 
         // process event attendees
         $attendees = new vectorattendee;
         foreach ((array)$object['attendees'] as $i => $attendee) {
             if ($attendee['role'] == 'ORGANIZER') {
                 $object['organizer'] = $attendee;
             }
             else if ($attendee['email'] != $object['organizer']['email']) {
                 $cr = new ContactReference(ContactReference::EmailReference, $attendee['email']);
                 $cr->setName($attendee['name']);
 
                 // set attendee RSVP if missing
                 if (!isset($attendee['rsvp'])) {
                     $object['attendees'][$i]['rsvp'] = $attendee['rsvp'] = $reschedule;
                 }
 
                 $att = new Attendee;
                 $att->setContact($cr);
                 $att->setPartStat($this->part_status_map[$attendee['status']]);
                 $att->setRole($this->role_map[$attendee['role']] ? $this->role_map[$attendee['role']] : kolabformat::Required);
                 $att->setCutype($this->cutype_map[$attendee['cutype']] ? $this->cutype_map[$attendee['cutype']] : kolabformat::CutypeIndividual);
                 $att->setRSVP((bool)$attendee['rsvp']);
 
                 if (!empty($attendee['delegated-from'])) {
                     $vdelegators = new vectorcontactref;
                     foreach ((array)$attendee['delegated-from'] as $delegator) {
                         $vdelegators->push(new ContactReference(ContactReference::EmailReference, $delegator));
                     }
                     $att->setDelegatedFrom($vdelegators);
                 }
                 if (!empty($attendee['delegated-to'])) {
                     $vdelegatees = new vectorcontactref;
                     foreach ((array)$attendee['delegated-to'] as $delegatee) {
                         $vdelegatees->push(new ContactReference(ContactReference::EmailReference, $delegatee));
                     }
                     $att->setDelegatedTo($vdelegatees);
                 }
 
                 if ($att->isValid()) {
                     $attendees->push($att);
                 }
                 else {
                     rcube::raise_error(array(
                         'code' => 600, 'type' => 'php',
                         'file' => __FILE__, 'line' => __LINE__,
                         'message' => "Invalid event attendee: " . json_encode($attendee),
                     ), true);
                 }
             }
         }
         $this->obj->setAttendees($attendees);
 
         if ($object['organizer']) {
             $organizer = new ContactReference(ContactReference::EmailReference, $object['organizer']['email']);
             $organizer->setName($object['organizer']['name']);
             $this->obj->setOrganizer($organizer);
         }
 
         // save recurrence rule
         $rr = new RecurrenceRule;
         $rr->setFrequency(RecurrenceRule::FreqNone);
 
         if ($object['recurrence'] && !empty($object['recurrence']['FREQ'])) {
             $rr->setFrequency($this->rrule_type_map[$object['recurrence']['FREQ']]);
 
             if ($object['recurrence']['INTERVAL'])
                 $rr->setInterval(intval($object['recurrence']['INTERVAL']));
 
             if ($object['recurrence']['BYDAY']) {
                 $byday = new vectordaypos;
                 foreach (explode(',', $object['recurrence']['BYDAY']) as $day) {
                     $occurrence = 0;
                     if (preg_match('/^([\d-]+)([A-Z]+)$/', $day, $m)) {
                         $occurrence = intval($m[1]);
                         $day = $m[2];
                     }
                     if (isset($this->weekday_map[$day]))
                         $byday->push(new DayPos($occurrence, $this->weekday_map[$day]));
                 }
                 $rr->setByday($byday);
             }
 
             if ($object['recurrence']['BYMONTHDAY']) {
                 $bymday = new vectori;
                 foreach (explode(',', $object['recurrence']['BYMONTHDAY']) as $day)
                     $bymday->push(intval($day));
                 $rr->setBymonthday($bymday);
             }
 
             if ($object['recurrence']['BYMONTH']) {
                 $bymonth = new vectori;
                 foreach (explode(',', $object['recurrence']['BYMONTH']) as $month)
                     $bymonth->push(intval($month));
                 $rr->setBymonth($bymonth);
             }
 
             if ($object['recurrence']['COUNT'])
                 $rr->setCount(intval($object['recurrence']['COUNT']));
             else if ($object['recurrence']['UNTIL'])
                 $rr->setEnd(self::get_datetime($object['recurrence']['UNTIL'], null, true));
 
             if ($rr->isValid()) {
                 // add exception dates (only if recurrence rule is valid)
                 $exdates = new vectordatetime;
                 foreach ((array)$object['recurrence']['EXDATE'] as $exdate)
                     $exdates->push(self::get_datetime($exdate, null, true));
                 $this->obj->setExceptionDates($exdates);
             }
             else {
                 rcube::raise_error(array(
                     'code' => 600, 'type' => 'php',
                     'file' => __FILE__, 'line' => __LINE__,
                     'message' => "Invalid event recurrence rule: " . json_encode($object['recurrence']),
                 ), true);
             }
         }
 
         $this->obj->setRecurrenceRule($rr);
 
         // save recurrence dates (aka RDATE)
         if (!empty($object['recurrence']['RDATE'])) {
             $rdates = new vectordatetime;
             foreach ((array)$object['recurrence']['RDATE'] as $rdate)
                 $rdates->push(self::get_datetime($rdate, null, true));
             $this->obj->setRecurrenceDates($rdates);
         }
 
         // save alarm
         $valarms = new vectoralarm;
         if ($object['valarms']) {
             foreach ($object['valarms'] as $valarm) {
                 if (!array_key_exists($valarm['action'], $this->alarm_type_map)) {
                     continue;  // skip unknown alarm types
                 }
 
                 if ($valarm['action'] == 'EMAIL') {
                     $recipients = new vectorcontactref;
                     foreach (($valarm['attendees'] ?: array($object['_owner'])) as $email) {
                         $recipients->push(new ContactReference(ContactReference::EmailReference, $email));
                     }
                     $alarm = new Alarm(
                         strval($valarm['summary'] ?: $object['title']),
                         strval($valarm['description'] ?: $object['description']),
                         $recipients
                     );
                 }
                 else if ($valarm['action'] == 'AUDIO') {
                     $attach = new Attachment;
                     $attach->setUri($valarm['uri'] ?: 'null', 'unknown');
                     $alarm = new Alarm($attach);
                 }
                 else {
                     // action == DISPLAY
                     $alarm = new Alarm(strval($valarm['summary'] ?: $object['title']));
                 }
 
                 if (is_object($valarm['trigger']) && $valarm['trigger'] instanceof DateTime) {
                     $alarm->setStart(self::get_datetime($valarm['trigger'], new DateTimeZone('UTC')));
                 }
                 else {
                     try {
-                        $prefix = $valarm['trigger'][0];
-                        $period = new DateInterval(preg_replace('/[^0-9PTWDHMS]/', '', $valarm['trigger']));
-                        $duration = new Duration($period->d, $period->h, $period->i, $period->s, $prefix == '-');
+                        $period   = new DateInterval(preg_replace('/[^0-9PTWDHMS]/', '', $valarm['trigger']));
+                        $duration = new Duration($period->d, $period->h, $period->i, $period->s, $valarm['trigger'][0] == '-');
                     }
                     catch (Exception $e) {
                         // skip alarm with invalid trigger values
                         rcube::raise_error($e, true);
                         continue;
                     }
 
-                    $alarm->setRelativeStart($duration, $prefix == '-' ? kolabformat::Start : kolabformat::End);
+                    $related = strtoupper($valarm['related']) == 'END' ? kolabformat::End : kolabformat::Start;
+                    $alarm->setRelativeStart($duration, $related);
                 }
 
                 if ($valarm['duration']) {
                     try {
                         $d = new DateInterval($valarm['duration']);
                         $duration = new Duration($d->d, $d->h, $d->i, $d->s);
                         $alarm->setDuration($duration, intval($valarm['repeat']));
                     }
                     catch (Exception $e) {
                         // ignore
                     }
                 }
 
                 $valarms->push($alarm);
             }
         }
         // legacy support
         else if ($object['alarms']) {
             list($offset, $type) = explode(":", $object['alarms']);
 
             if ($type == 'EMAIL' && !empty($object['_owner'])) {  // email alarms implicitly go to event owner
                 $recipients = new vectorcontactref;
                 $recipients->push(new ContactReference(ContactReference::EmailReference, $object['_owner']));
                 $alarm = new Alarm($object['title'], strval($object['description']), $recipients);
             }
             else {  // default: display alarm
                 $alarm = new Alarm($object['title']);
             }
 
             if (preg_match('/^@(\d+)/', $offset, $d)) {
                 $alarm->setStart(self::get_datetime($d[1], new DateTimeZone('UTC')));
             }
             else if (preg_match('/^([-+]?)P?T?(\d+)([SMHDW])/', $offset, $d)) {
                 $days = $hours = $minutes = $seconds = 0;
                 switch ($d[3]) {
                     case 'W': $days  = 7*intval($d[2]); break;
                     case 'D': $days    = intval($d[2]); break;
                     case 'H': $hours   = intval($d[2]); break;
                     case 'M': $minutes = intval($d[2]); break;
                     case 'S': $seconds = intval($d[2]); break;
                 }
                 $alarm->setRelativeStart(new Duration($days, $hours, $minutes, $seconds, $d[1] == '-'), $d[1] == '-' ? kolabformat::Start : kolabformat::End);
             }
 
             $valarms->push($alarm);
         }
         $this->obj->setAlarms($valarms);
 
         $this->set_attachments($object);
     }
 
     /**
      * Return the reference date for recurrence and alarms
      *
      * @return mixed DateTime instance of null if no refdate is available
      */
     public function get_reference_date()
     {
         if ($this->data['start'] && $this->data['start'] instanceof DateTime) {
             return $this->data['start'];
         }
 
         return self::php_datetime($this->obj->start());
     }
 
     /**
      * Callback for kolab_storage_cache to get words to index for fulltext search
      *
      * @return array List of words to save in cache
      */
     public function get_words($obj = null)
     {
         $data = '';
         $object = $obj ?: $this->data;
 
         foreach (self::$fulltext_cols as $colname) {
             list($col, $field) = explode(':', $colname);
 
             if ($field) {
                 $a = array();
                 foreach ((array)$object[$col] as $attr)
                     $a[] = $attr[$field];
                 $val = join(' ', $a);
             }
             else {
                 $val = is_array($object[$col]) ? join(' ', $object[$col]) : $object[$col];
             }
 
             if (strlen($val))
                 $data .= $val . ' ';
         }
 
         $words = rcube_utils::normalize_string($data, true);
 
         // collect words from recurrence exceptions
         if (is_array($object['exceptions'])) {
             foreach ($object['exceptions'] as $exception) {
                 $words = array_merge($words, $this->get_words($exception));
             }
         }
 
         return array_unique($words);
     }
 
     /**
      * Callback for kolab_storage_cache to get object specific tags to cache
      *
      * @return array List of tags to save in cache
      */
     public function get_tags($obj = null)
     {
         $tags = array();
         $object = $obj ?: $this->data;
 
         if (!empty($object['valarms'])) {
             $tags[] = 'x-has-alarms';
         }
 
         // create tags reflecting participant status
         if (is_array($object['attendees'])) {
             foreach ($object['attendees'] as $attendee) {
                 if (!empty($attendee['email']) && !empty($attendee['status']))
                     $tags[] = 'x-partstat:' . $attendee['email'] . ':' . strtolower($attendee['status']);
             }
         }
 
         // collect tags from recurrence exceptions
         if (is_array($object['exceptions'])) {
             foreach ($object['exceptions'] as $exception) {
                 $tags = array_merge($tags, $this->get_tags($exception));
             }
         }
 
         if (!empty($object['status'])) {
           $tags[] = 'x-status:' . strtolower($object['status']);
         }
 
         return array_unique($tags);
     }
 
     /**
      * Identify changes considered relevant for scheduling
      * 
      * @param array Hash array with NEW object properties
      * @param array Hash array with OLD object properties
      *
      * @return boolean True if changes affect scheduling, False otherwise
      */
     public function check_rescheduling($object, $old = null)
     {
         $reschedule = false;
 
         if (!is_array($old)) {
             $old = $this->data['uid'] ? $this->data : $this->to_array();
         }
 
         foreach ($this->_scheduling_properties ?: self::$scheduling_properties as $prop) {
             $a = $old[$prop];
             $b = $object[$prop];
             if ($object['allday'] && ($prop == 'start' || $prop == 'end') && $a instanceof DateTime && $b instanceof DateTime) {
                 $a = $a->format('Y-m-d');
                 $b = $b->format('Y-m-d');
             }
             if ($prop == 'recurrence' && is_array($a) && is_array($b)) {
                 unset($a['EXCEPTIONS'], $b['EXCEPTIONS']);
                 $a = array_filter($a);
                 $b = array_filter($b);
 
                 // advanced rrule comparison: no rescheduling if series was shortened
                 if ($a['COUNT'] && $b['COUNT'] && $b['COUNT'] < $a['COUNT']) {
                   unset($a['COUNT'], $b['COUNT']);
                 }
                 else if ($a['UNTIL'] && $b['UNTIL'] && $b['UNTIL'] < $a['UNTIL']) {
                   unset($a['UNTIL'], $b['UNTIL']);
                 }
             }
             if ($a != $b) {
                 $reschedule = true;
                 break;
             }
         }
 
         return $reschedule;
     }
 }
\ No newline at end of file
diff --git a/plugins/tasklist/tasklist_ui.php b/plugins/tasklist/tasklist_ui.php
index 97b16334..0315d8f8 100644
--- a/plugins/tasklist/tasklist_ui.php
+++ b/plugins/tasklist/tasklist_ui.php
@@ -1,540 +1,541 @@
 <?php
 /**
  * User Interface class for the Tasklist plugin
  *
  * @version @package_version@
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2012-2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
  * published by the Free Software Foundation, either version 3 of the
  * License, or (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU Affero General Public License for more details.
  *
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
 
 class tasklist_ui
 {
     private $rc;
     private $plugin;
     private $ready = false;
     private $gui_objects = array();
 
     function __construct($plugin)
     {
         $this->plugin = $plugin;
         $this->rc     = $plugin->rc;
     }
 
     /**
      * Calendar UI initialization and requests handlers
      */
     public function init()
     {
         if ($this->ready) {
             return;
         }
 
         // add taskbar button
         $this->plugin->add_button(array(
             'command'    => 'tasks',
             'class'      => 'button-tasklist',
             'classsel'   => 'button-tasklist button-selected',
             'innerclass' => 'button-inner',
             'label'      => 'tasklist.navtitle',
         ), 'taskbar');
 
         $this->plugin->include_stylesheet($this->plugin->local_skin_path() . '/tasklist.css');
 
         if ($this->rc->task == 'mail' || $this->rc->task == 'tasks') {
             jqueryui::tagedit();
 
             $this->plugin->include_script('tasklist_base.js');
 
             // copy config to client
             $this->rc->output->set_env('tasklist_settings', $this->load_settings());
 
             // initialize attendees autocompletion
             $this->rc->autocomplete_init();
         }
 
         $this->ready = true;
     }
 
     /**
      *
      */
     function load_settings()
     {
         $settings = array();
 
         $settings['invite_shared'] = (int)$this->rc->config->get('calendar_allow_invite_shared', 0);
         $settings['itip_notify']   = (int)$this->rc->config->get('calendar_itip_send_option', 3);
         $settings['sort_col']      = $this->rc->config->get('tasklist_sort_col', '');
         $settings['sort_order']    = $this->rc->config->get('tasklist_sort_order', 'asc');
 
         // get user identity to create default attendee
         foreach ($this->rc->user->list_emails() as $rec) {
             if (!$identity)
                 $identity = $rec;
 
             $identity['emails'][] = $rec['email'];
             $settings['identities'][$rec['identity_id']] = $rec['email'];
         }
 
         $identity['emails'][] = $this->rc->user->get_username();
         $settings['identity'] = array(
             'name'   => $identity['name'],
             'email'  => strtolower($identity['email']),
             'emails' => ';' . strtolower(join(';', $identity['emails']))
         );
 
         if ($list = rcube_utils::get_input_value('_list', rcube_utils::INPUT_GPC)) {
             $settings['selected_list'] = $list;
         }
         if ($list && ($id = rcube_utils::get_input_value('_id', rcube_utils::INPUT_GPC))) {
             $settings['selected_id'] = $id;
 
             // check if the referenced task is completed
             $task = $this->plugin->driver->get_task(array('id' => $id, 'list' => $list));
             if ($task && $this->plugin->driver->is_complete($task)) {
                 $settings['selected_filter'] = 'complete';
             }
         }
         else if ($filter = rcube_utils::get_input_value('_filter', rcube_utils::INPUT_GPC)) {
             $settings['selected_filter'] = $filter;
         }
 
         return $settings;
     }
 
     /**
      * Render a HTML select box for user identity selection
      */
     function identity_select($attrib = array())
     {
         $attrib['name'] = 'identity';
         $select         = new html_select($attrib);
         $identities     = $this->rc->user->list_emails();
 
         foreach ($identities as $ident) {
             $select->add(format_email_recipient($ident['email'], $ident['name']), $ident['identity_id']);
         }
 
         return $select->show(null);
     }
 
     /**
     * Register handler methods for the template engine
     */
     public function init_templates()
     {
         $this->plugin->register_handler('plugin.tasklists', array($this, 'tasklists'));
         $this->plugin->register_handler('plugin.tasklist_select', array($this, 'tasklist_select'));
         $this->plugin->register_handler('plugin.status_select', array($this, 'status_select'));
         $this->plugin->register_handler('plugin.searchform', array($this->rc->output, 'search_form'));
         $this->plugin->register_handler('plugin.quickaddform', array($this, 'quickadd_form'));
         $this->plugin->register_handler('plugin.tasks', array($this, 'tasks_resultview'));
         $this->plugin->register_handler('plugin.tagslist', array($this, 'tagslist'));
         $this->plugin->register_handler('plugin.tags_editline', array($this, 'tags_editline'));
         $this->plugin->register_handler('plugin.alarm_select', array($this, 'alarm_select'));
         $this->plugin->register_handler('plugin.recurrence_form', array($this->plugin->lib, 'recurrence_form'));
         $this->plugin->register_handler('plugin.attachments_form', array($this, 'attachments_form'));
         $this->plugin->register_handler('plugin.attachments_list', array($this, 'attachments_list'));
         $this->plugin->register_handler('plugin.filedroparea', array($this, 'file_drop_area'));
         $this->plugin->register_handler('plugin.attendees_list', array($this, 'attendees_list'));
         $this->plugin->register_handler('plugin.attendees_form', array($this, 'attendees_form'));
         $this->plugin->register_handler('plugin.identity_select', array($this, 'identity_select'));
         $this->plugin->register_handler('plugin.edit_attendees_notify', array($this, 'edit_attendees_notify'));
         $this->plugin->register_handler('plugin.task_rsvp_buttons', array($this->plugin->itip, 'itip_rsvp_buttons'));
         $this->plugin->register_handler('plugin.object_changelog_table', array('libkolab', 'object_changelog_table'));
 
         jqueryui::tagedit();
 
         $this->plugin->include_script('tasklist.js');
         $this->rc->output->include_script('treelist.js');
 
         // include kolab folderlist widget if available
         if (in_array('libkolab', $this->plugin->api->loaded_plugins())) {
             $this->plugin->api->include_script('libkolab/js/folderlist.js');
             $this->plugin->api->include_script('libkolab/js/audittrail.js');
         }
     }
 
     /**
      *
      */
     public function tasklists($attrib = array())
     {
         $tree = true;
         $jsenv = array();
         $lists = $this->plugin->driver->get_lists($tree);
 
         // walk folder tree
         if (is_object($tree)) {
             $html = $this->list_tree_html($tree, $lists, $jsenv, $attrib);
         }
         else {
             // fall-back to flat folder listing
             $attrib['class'] .= ' flat';
 
             $html = '';
             foreach ((array)$lists as $id => $prop) {
                 if ($attrib['activeonly'] && !$prop['active'])
                   continue;
 
                 $html .= html::tag('li', array(
                         'id' => 'rcmlitasklist' . rcube_utils::html_identifier($id),
                         'class' => $prop['group'],
                     ),
                     $this->tasklist_list_item($id, $prop, $jsenv, $attrib['activeonly'])
                 );
             }
         }
 
         $this->rc->output->set_env('tasklists', $jsenv);
         $this->register_gui_object('tasklistslist', $attrib['id']);
 
         return html::tag('ul', $attrib, $html, html::$common_attrib);
     }
 
     /**
      * Return html for a structured list <ul> for the folder tree
      */
     public function list_tree_html($node, $data, &$jsenv, $attrib)
     {
         $out = '';
         foreach ($node->children as $folder) {
             $id = $folder->id;
             $prop = $data[$id];
             $is_collapsed = false; // TODO: determine this somehow?
 
             $content = $this->tasklist_list_item($id, $prop, $jsenv, $attrib['activeonly']);
 
             if (!empty($folder->children)) {
                 $content .= html::tag('ul', array('style' => ($is_collapsed ? "display:none;" : null)),
                     $this->list_tree_html($folder, $data, $jsenv, $attrib));
             }
 
             if (strlen($content)) {
                 $out .= html::tag('li', array(
                       'id' => 'rcmlitasklist' . rcube_utils::html_identifier($id),
                       'class' => $prop['group'] . ($prop['virtual'] ? ' virtual' : ''),
                     ),
                     $content);
             }
         }
 
         return $out;
     }
 
     /**
      * Helper method to build a tasklist item (HTML content and js data)
      */
     public function tasklist_list_item($id, $prop, &$jsenv, $activeonly = false)
     {
         // enrich list properties with settings from the driver
         if (!$prop['virtual']) {
             unset($prop['user_id']);
             $prop['alarms']      = $this->plugin->driver->alarms;
             $prop['undelete']    = $this->plugin->driver->undelete;
             $prop['sortable']    = $this->plugin->driver->sortable;
             $prop['attachments'] = $this->plugin->driver->attachments;
             $prop['attendees']   = $this->plugin->driver->attendees;
             $prop['caldavurl']   = $this->plugin->driver->tasklist_caldav_url($prop);
             $jsenv[$id] = $prop;
         }
 
         $classes = array('tasklist');
         $title = $prop['title'] ?: ($prop['name'] != $prop['listname'] || strlen($prop['name']) > 25 ?
           html_entity_decode($prop['name'], ENT_COMPAT, RCMAIL_CHARSET) : '');
 
         if ($prop['virtual'])
             $classes[] = 'virtual';
         else if (!$prop['editable'])
             $classes[] = 'readonly';
         if ($prop['subscribed'])
             $classes[] = 'subscribed';
         if ($prop['class'])
             $classes[] = $prop['class'];
 
         if (!$activeonly || $prop['active']) {
             $label_id = 'tl:' . $id;
             return html::div(join(' ', $classes),
                 html::span(array('class' => 'listname', 'title' => $title, 'id' => $label_id), $prop['listname'] ?: $prop['name']) .
                   ($prop['virtual'] ? '' :
                       html::tag('input', array('type' => 'checkbox', 'name' => '_list[]', 'value' => $id, 'checked' => $prop['active'], 'aria-labelledby' => $label_id)) .
                       html::span('actions', 
                           ($prop['removable'] ? html::a(array('href' => '#', 'class' => 'remove', 'title' => $this->plugin->gettext('removelist')), ' ') : '') .
                           html::a(array('href' => '#', 'class' => 'quickview', 'title' => $this->plugin->gettext('focusview'), 'role' => 'checkbox', 'aria-checked' => 'false'), ' ') .
                           (isset($prop['subscribed']) ? html::a(array('href' => '#', 'class' => 'subscribed', 'title' => $this->plugin->gettext('tasklistsubscribe'), 'role' => 'checkbox', 'aria-checked' => $prop['subscribed'] ? 'true' : 'false'), ' ') : '')
                       )
                 )
             );
         }
 
         return '';
     }
 
     /**
      * Render HTML form for task status selector
      */
     function status_select($attrib = array())
     {
         $attrib['name'] = 'status';
         $select = new html_select($attrib);
         $select->add('---', '');
         $select->add($this->plugin->gettext('status-needs-action'), 'NEEDS-ACTION');
         $select->add($this->plugin->gettext('status-in-process'),   'IN-PROCESS');
         $select->add($this->plugin->gettext('status-completed'),    'COMPLETED');
         $select->add($this->plugin->gettext('status-cancelled'),    'CANCELLED');
 
         return $select->show(null);
     }
 
     /**
      * Render a HTML select box for list selection
      */
     function tasklist_select($attrib = array())
     {
         $attrib['name']       = 'list';
         $attrib['is_escaped'] = true;
         $select = new html_select($attrib);
         $default = null;
 
         foreach ((array)$this->plugin->driver->get_lists() as $id => $prop) {
             if ($prop['editable'] || strpos($prop['rights'], 'i') !== false) {
                 $select->add($prop['name'], $id);
                 if (!$default || $prop['default'])
                     $default = $id;
             }
         }
 
         return $select->show($default);
     }
 
 
     function tasklist_editform($action, $list = array())
     {
         $fields = array(
             'name' => array(
                 'id' => 'taskedit-tasklistame',
                 'label' => $this->plugin->gettext('listname'),
                 'value' => html::tag('input', array('id' => 'taskedit-tasklistame', 'name' => 'name', 'type' => 'text', 'class' => 'text', 'size' => 40)),
             ),
 /*
             'color' => array(
                 'id' => 'taskedit-color',
                 'label' => $this->plugin->gettext('color'),
                 'value' => html::tag('input', array('id' => 'taskedit-color', 'name' => 'color', 'type' => 'text', 'class' => 'text colorpicker', 'size' => 6)),
             ),
 */
             'showalarms' => array(
                 'id' => 'taskedit-showalarms',
                 'label' => $this->plugin->gettext('showalarms'),
                 'value' => html::tag('input', array('id' => 'taskedit-showalarms', 'name' => 'color', 'type' => 'checkbox')),
             ),
         );
 
         return html::tag('form', array('action' => "#", 'method' => "post", 'id' => 'tasklisteditform'),
             $this->plugin->driver->tasklist_edit_form($action, $list, $fields)
         );
     }
 
     /**
      * Render HTML form for alarm configuration
      */
     function alarm_select($attrib = array())
     {
+        $attrib['_type'] = 'task';
         return $this->plugin->lib->alarm_select($attrib, $this->plugin->driver->alarm_types, $this->plugin->driver->alarm_absolute);
     }
 
     /**
      *
      */
     function quickadd_form($attrib)
     {
         $attrib += array('action' => $this->rc->url('add'), 'method' => 'post', 'id' => 'quickaddform');
 
         $label = html::label(array('for' => 'quickaddinput', 'class' => 'voice'), $this->plugin->gettext('quickaddinput'));
         $input = new html_inputfield(array('name' => 'text', 'id' => 'quickaddinput'));
         $button = html::tag('input', array('type' => 'submit', 'value' => '+', 'title' => $this->plugin->gettext('createtask'), 'class' => 'button mainaction'));
 
         $this->register_gui_object('quickaddform', $attrib['id']);
         return html::tag('form', $attrib, $label . $input->show() . $button);
     }
 
     /**
      * The result view
      */
     function tasks_resultview($attrib)
     {
         $attrib += array('id' => 'rcmtaskslist');
 
         $this->register_gui_object('resultlist', $attrib['id']);
 
         unset($attrib['name']);
         return html::tag('ul', $attrib, '');
     }
 
     /**
      * Container for a tags cloud
      */
     function tagslist($attrib)
     {
         $attrib += array('id' => 'rcmtasktagslist');
         unset($attrib['name']);
 
         $this->register_gui_object('tagslist', $attrib['id']);
         return html::tag('ul', $attrib, '');
     }
 
     /**
      * Interactive UI element to add/remove tags
      */
     function tags_editline($attrib)
     {
         $attrib += array('id' => 'rcmtasktagsedit');
         $this->register_gui_object('edittagline', $attrib['id']);
 
         $input = new html_inputfield(array('name' => 'tags[]', 'class' => 'tag', 'size' => $attrib['size'], 'tabindex' => $attrib['tabindex']));
         unset($attrib['tabindex']);
         return html::div($attrib, $input->show(''));
     }
 
     /**
      * Generate HTML element for attachments list
      */
     function attachments_list($attrib = array())
     {
         if (!$attrib['id'])
             $attrib['id'] = 'rcmtaskattachmentlist';
 
         $this->register_gui_object('attachmentlist', $attrib['id']);
 
         return html::tag('ul', $attrib, '', html::$common_attrib);
     }
 
     /**
      * Generate the form for event attachments upload
      */
     function attachments_form($attrib = array())
     {
         // add ID if not given
         if (!$attrib['id'])
             $attrib['id'] = 'rcmtaskuploadform';
 
         // Get max filesize, enable upload progress bar
         $max_filesize = rcube_upload_init();
 
         $button = new html_inputfield(array('type' => 'button'));
         $input = new html_inputfield(array(
             'type' => 'file',
             'name' => '_attachments[]',
             'multiple' => 'multiple',
             'size' => $attrib['attachmentfieldsize'],
         ));
 
         return html::div($attrib,
             html::div(null, $input->show()) .
             html::div('formbuttons', $button->show(rcube_label('upload'), array('class' => 'button mainaction',
                 'onclick' => JS_OBJECT_NAME . ".upload_file(this.form)"))) .
             html::div('hint', rcube_label(array('name' => 'maxuploadsize', 'vars' => array('size' => $max_filesize))))
         );
     }
 
     /**
      * Register UI object for HTML5 drag & drop file upload
      */
     function file_drop_area($attrib = array())
     {
         if ($attrib['id']) {
             $this->register_gui_object('filedrop', $attrib['id']);
             $this->rc->output->set_env('filedrop', array('action' => 'upload', 'fieldname' => '_attachments'));
         }
     }
 
     /**
      *
      */
     function attendees_list($attrib = array())
     {
         // add "noreply" checkbox to attendees table only
         $invitations = strpos($attrib['id'], 'attend') !== false;
 
         $invite = new html_checkbox(array('value' => 1, 'id' => 'edit-attendees-invite'));
         $table  = new html_table(array('cols' => 4 + intval($invitations), 'border' => 0, 'cellpadding' => 0, 'class' => 'rectable'));
 
 //      $table->add_header('role', $this->plugin->gettext('role'));
         $table->add_header('name', $this->plugin->gettext($attrib['coltitle'] ?: 'attendee'));
         $table->add_header('confirmstate', $this->plugin->gettext('confirmstate'));
         if ($invitations) {
             $table->add_header(array('class' => 'invite', 'title' => $this->plugin->gettext('sendinvitations')),
                 $invite->show(1) . html::label('edit-attendees-invite', $this->plugin->gettext('sendinvitations')));
         }
         $table->add_header('options', '');
 
         // hide invite column if disabled by config
         $itip_notify = (int)$this->rc->config->get('calendar_itip_send_option', 3);
         if ($invitations && !($itip_notify & 2)) {
             $css = sprintf('#%s td.invite, #%s th.invite { display:none !important }', $attrib['id'], $attrib['id']);
             $this->rc->output->add_footer(html::tag('style', array('type' => 'text/css'), $css));
         }
 
         return $table->show($attrib);
     }
 
     /**
      *
      */
     function attendees_form($attrib = array())
     {
         $input    = new html_inputfield(array('name' => 'participant', 'id' => 'edit-attendee-name', 'size' => 30));
         $textarea = new html_textarea(array('name' => 'comment', 'id' => 'edit-attendees-comment',
             'rows' => 4, 'cols' => 55, 'title' => $this->plugin->gettext('itipcommenttitle')));
 
         return html::div($attrib,
             html::div(null, $input->show() . " " .
                 html::tag('input', array('type' => 'button', 'class' => 'button', 'id' => 'edit-attendee-add', 'value' => $this->plugin->gettext('addattendee')))
                 // . " " . html::tag('input', array('type' => 'button', 'class' => 'button', 'id' => 'edit-attendee-schedule', 'value' => $this->plugin->gettext('scheduletime').'...'))
                 ) .
             html::p('attendees-commentbox', html::label(null, $this->plugin->gettext('itipcomment') . $textarea->show()))
         );
     }
 
     /**
      *
      */
     function edit_attendees_notify($attrib = array())
     {
         $checkbox = new html_checkbox(array('name' => '_notify', 'id' => 'edit-attendees-donotify', 'value' => 1));
         return html::div($attrib, html::label(null, $checkbox->show(1) . ' ' . $this->plugin->gettext('sendnotifications')));
     }
 
     /**
      * Wrapper for rcube_output_html::add_gui_object()
      */
     function register_gui_object($name, $id)
     {
         $this->gui_objects[$name] = $id;
         $this->rc->output->add_gui_object($name, $id);
     }
 
     /**
      * Getter for registered gui objects.
      * (for manual registration when loading the inline UI)
      */
     function get_gui_objects()
     {
         return $this->gui_objects;
     }
 }