[horde] Problem kronolith

[Ralf Lang]

Hi Ruud,

yes, I read it that way. Now telling Thunderbird to change is beyond me
unfortunately. It's a wholly different beast I fear.

Ruud Baart <r.j.baart at prompt.nl> schrieb am Di., 24. Feb. 2026, 15:40:

> Thank you for this explanation.
>
> Are you referring to this in the RFC 5545:
>
> "The use of local time in a DATE-TIME or TIME value without the  "TZID"
> property parameter is to be interpreted as floating time, regardless of the
> existence of "VTIMEZONE" calendar components in the iCalendar object."
>
> This means: no timezone -> local time. And what local time is that depends
> on where you are. Correct?
>
> It also means the Thunderbird calendar cache is faulty. It should not
> store "UTC" if timezone is empty. Correct?
>
>
>
> Op 2026-02-24 om 15:22 schreef Ralf Lang:
>
> Hi Ruud,
>
> it's a good idea to increase data quality but it also introduces some new
> problems.
> VEVENT components without explicit VTIMEZONE entries are valid in
> iCalendar (RFC 5545) and CalDAV, provided they follow specific formatting
> rules for their time values.
> We have to accept events, ics files, invitations etc from other software
> products or from legacy data imports.
>
> However we can define that we internally handle them with timezone and
> always create/export them with timezone.
> Which leads to a whole other category of fun whenever one software product
> uses a timezone another doesn't know.
>
> We will probably need to work on how exactly we achieve this timezone
> compatibility the right way.
>
>
> On Tue, Feb 24, 2026 at 3:13 PM Ruud Baart <r.j.baart at prompt.nl> wrote:
>
>> Hi,
>>
>> approximately 30,000 appointments are stored in the Horde database,
>> roughly half of which do not have a time zone stored. That works fine in
>> itself, but lately it has been causing problems in Thunderbird.
>>
>>     horde6=# select count(*) from kronolith_events where event_timezone
>> is null;
>>       count
>>     -------
>>       13677
>>     (1 row)
>>
>>     horde6=# select count(*) from kronolith_events where event_timezone
>> is not null;
>>       count
>>     -------
>>       17499
>>     (1 row)
>>
>> If I have analyzed it correctly, this is because Thunderbird's calendar
>> converts the null value to UTC in its cache (sqlite databases). That is
>> not the correct value. So registering an event works fine, but when you
>> reopen Thunderbird, the display is incorrect.
>>
>> I would like to see Horde make a time zone mandatory when storing
>> events. If the time zone is missing, it should take the time zone from
>> the preferences, and if that is not possible, it should take the system
>> time zone. I am not sure if my wish is already achievable through the
>> configuration of Horde.
>>
>> --
>>
>> Cordialement,
>>
>> *
>>
>> R.J. Baart
>>
>> *
>> --
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>
>