diff --git a/plugins/libkolab/README b/plugins/libkolab/README
index dc94da04..2cd6b7cc 100644
--- a/plugins/libkolab/README
+++ b/plugins/libkolab/README
@@ -1,37 +1,44 @@
 libkolab plugin to access to Kolab groupware 2.x data
 =====================================================
 
 The contained library classes establish a connection to the Kolab server
 and manage the access to the Kolab groupware objects stored in various
 IMAP folders. For reading and writing these objects, the Horde Kolab_Format
 packages are used.
 
 
 REQUIREMENTS
 ------------
 * PEAR: HTTP/Request2
 * PEAR: Net/URL2
 * Horde 5 Kolab_Format library from https://github.com/horde/horde
+  with patches from https://github.com/thomascube/horde
 
 
 INSTALLATION
 ------------
 To use local cache you need to create a dedicated table in Roundcube's database.
 To do so, execute the SQL commands in SQL/<yourdatabase>.sql
 
+Installing the Horde 5 library:
+
+$ git clone https://github.com/thomascube/horde.git horde-git
+$ cp -r horde-git/framework/Kolab_Format/lib/Horde <roundcube-dir>/plugins/libkolab/lib/Horde
+$ rm -rf horde-git
+
 
 CONFIGURATION
 -------------
 The following options can be configured in Roundcube's main config file
 or a local config file (config.inc.php) located in the plugin folder.
 
 // Enable caching of Kolab objects in local database
 $rcmail_config['kolab_cache'] = true;
 
 // Optional override of the URL to read and trigger Free/Busy information of Kolab users
 // Defaults to https://<imap-server->/freebusy
 $rcmail_config['kolab_freebusy_server'] = 'https://<some-host>/<freebusy-path>';
 
 // Set this option to disable SSL certificate checks when triggering Free/Busy (enabled by default)
 $rcmail_config['kolab_ssl_verify_peer'] = false;