Changing the time zone definitions in timezones.xml file in Kerio Connect

Time zones are defined in the timezones.xml definition file in Kerio Connect.

Each version of Kerio Connect includes a new version of the timezones.xml file. However, you can edit the file directly or download the latest time zone definition file attached to this article.


On October 26, 2014, Russia changes their time zones. A new file including these changes is available in the attachment section below this article.

Important notes

If you change the timezones.xml file, note the following:

  • Calendar events and tasks have time zone definitions saved within the event/task itself. You must create the event/task again to apply the new time zones.
  • All newly created events/tasks use the new time zone definitions.
  • Client applications (MS Outlook, Apple Calendars) use their own or system time zone definitions. Make sure you have everything updated in order to have the correct time zone definitions in all your email clients.

Updating the timezones.xml file automatically

To update the timezones.xml automatically, upgrade your Kerio Connect.

Updating the timezones.xml file manually

The timezones.xml file is located in the installation directory of the Kerio Connect server.

The default path is:

  • MS Windows — C:\Program Files\Kerio\MailServer
  • Linux — /opt/kerio/mailserver
  • Mas OS X — /usr/local/kerio/mailserver

To update the file, follow these steps:

  1. Stop the Kerio Connect server.
  2. Replace the timezones.xml with a new one.


Backup the original timezones.xml file.

  1. Start the Kerio Connect server.

Kerio Connect starts using the new time zone definitions for all newly created events.

Editing the timezones.xml file

You can edit the timezones.xml. The file contains two parts enclosed in the following tags: <abbr></abbr> and <zone></zone>.


All date and time definitions used in this description are defined in the RFC 2445.

Editing the <abbr> section

This section describes the time shift. This part is optional although it helps you to simplify reading of the configuration file.

The <abbr> section has the following properties:

  • <name> — The name of the time shift definition (the GMT/UTC offset)
  • <offset> — The value of the time shift in ±PThhHmmM format (hh means hours and mm means minutes, other letters are reserved).
  • <daylight> — If this value is true, the time zone definition uses the daylight saving time. If the value is false, the time zone does not use the daylight saving time.

Editing the <zone> section

This section defines the time zone.

The <zone> section has the following mandatory properties:

  • <name> — The name of the time zone. Kerio Connect uses this string when searching for the appropriate time zone.
  • <stdAbbr> — Name of the time shift defined in the <abbr> section or a direct value in ±hhmm (hh means hours and mm means minutes).
  • <cdoTimeZoneId> — This option is usually required by synchronization devices and maps the time zone definition to the appropriate time zone definition in the Microsoft definition table. This mapping table can be found on the Microsoft web page. This line can be specified multiple times to assign all appropriate time zone Ids to the time zone definition.

The following attributes are optional:

  • <daylightAbbr> — This is a time shift definition for the daylight saving time in the same format as the mandatory stdAbbr attribute.
  • <stdStart> — The date and time this definition becomes valid for the first time for the specified location. The format is yyyymmddThhmmss where y is year, m is month, d is day, h is hour, m is minute and s is second.
  • <daylightStart> — The date and time the daylight savings time becomes valid for the first time for the location. The format is yyyymmddThhmmss where y is year, m is month, d is day, h is hour, m is minute and s is second.
  • <stdRRule> — This option defines periodicity and frequency of changing to standard time. FREQ is the frequency of the change, BYMONTH is the month when the change occurs, BYMONTHDAY is the day when the change occurs (you can also use BYDAY which is the x-th day in a week or month). Example: FREQ=YEARLY;BYMONTH=9;BYMONTHDAY=22