[horde] Problem kronolith

[Ralf Lang]

I'm going to ask you to report things there if that's the way it works ;)
Impressive outcome!

Thank you for pushing this.

On Wed, Feb 25, 2026 at 2:08 PM <R.J.Baart at prompt.nl> wrote:

> Amazing, I really think I have a huge influence.
>
> The bug in Thunderbird seems to have been fixed this morning in the
> latest version of Thunderbird. It concerns Thunderbird Desktop Version
> 148.0, released February 24, 2026. I haven't checked it yet, but the
> release notes say “fixed: iCal imports misread unknown time zones as
> GMT, creating events at wrong times.”
>
> That's really fast.
>
>
> Op 2026-02-25 om 11:02 schreef Ruud Baart:
> > Thanks, I made a bug report in Bugzilla. Hope they find a solution.
> >
> > My (ugly) temporary work around for the moment is to make a progresql
> > cronjob that looks for null values in the kronolith_events table and
> > fill these with our timezone (Europe/Paris) and adjust the
> > modification time. With a sync of the calendar it should be fine for
> > the users.
> >
> >
> > Op 2026-02-25 om 10:54 schreef 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.
> >>>
>
>