[horde] Problem kronolith

[Ruud Baart]

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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