Kolab16: Not a valid olson timezone: Etc/GMT-1
Closed, ResolvedPublic


I don't know which client or device sends the strange timezone Etc/GMT-1.
Feel free to close this issue as WONTFIX. I just wanted to report it, in case this problem happens for other people too.

PHP Error: kolabformat Error:  0:   Not a valid olson timezone: Etc/GMT-1 in /usr/share/roundcubemail/plugins/libkolab/lib/kolab_format.php on line 381 (POST /roundcubemail/qJd7gxTiu00OHwCW/?_task=calendar&_action=event)
PHP Error: Error saving event object to Kolab server in /usr/share/roundcubemail/plugins/calendar/drivers/kolab/kolab_calendar.php on line 470 (POST /roundcubemail/qJd7gxTiu00OHwCW/?_task=calendar&_action=event)

the error is from here:

olsonTimezones are defined in

rpm -qa | grep libkolab



Ticket Type

Event Timeline

pokorra created this task.Oct 18 2017, 2:13 PM
pokorra added a project: Libraries.
pokorra added a subscriber: Library Developers.

I got more details: the client is Firefox 56 running on Windows Server 2012 R2. The timezone setting for the user in Roundcube is "auto".

I checked how the timezone is determined: at login time, the timezone is detected:

and then passed to Roundcube:

for timezone detection, the library is used.
from their file I cannot find how they would pass Etc/GMT-1:

I will try to find access to a Windows Server 2012 R2...

pokorra added a comment.EditedOct 19 2017, 12:02 PM

It does not depend on Windows Server version.
It does not depend on Firefox version either.

On the same server, with Firefox 56.0.1 installed, I get with one Windows user profile "Europe/Berlin", and with another windows user I get "Etc/GMT-1".

The jstz library uses

According to Firefox Bugzilla (, Firefox is using the Windows function localtime.

So I wonder where to fix this issue? Either in the jstz library, or in libkolabxml?
At the moment I have a workaround in /usr/share/roundcubemail/plugins/calendar/drivers/kolab/kolab_calendar.php

I have filed now a bug at the jstz library, because I guess that would be the cleanest solution.
If that ignores Etc timezones coming from the internationalization API from the browser, then it calculates a proper Olson timezone.

pasik added a subscriber: pasik.Nov 25 2017, 2:30 PM
machniak closed this task as Resolved.Dec 16 2018, 12:37 PM
machniak claimed this task.
machniak added a project: Roundcube.
machniak added a subscriber: machniak.

Because jsTimezoneDetect is not very active project I decided to add a workaround on PHP side. Fixed in

If needed we can also use the new rcube_config::resolve_timezone_alias method in Kolab plugins' code. E.g. might be needed to catch deprecated timezones in input from iTip messages or CalDAV clients.