[kronolith] Sunbird vs Kronolith vs german summertime

[Sven Hoexter]

Hi,
I started to digg into this problem for a friend using Mozilla Sunbird
syncing against a Kronolith instance. After the switch to the german
summertime every reoccurring event is listed +1h by Sunbird but is still
correctly displayed in the webcalendar.

Looking at the ics files sent to kronolith and exported locally I see
that the VTIMEZONE block and TZIDs are missing in the export from kronolith.#
This in turn leads to the wrongly calculated start and end times in Sunbird.

Searching in the kronolith bugreports I found that VTIMEZONES should be
supported since 3.1.4 and the installation in use is version 3.3.11.

Any ideas/hints on how to fix this issue? Or a pointer where to start
searching in the source code?

Regards,
Sven