Lester Caine <lester@lsces.co.uk> wrote on Wed, 28 Oct 2015 at 23:03:56 +0000 in <5631545C.8080704@lsces.co.uk>:
This doesn't feel like a zoneinfo issue; it's a user interface design question for calendar applications.
YES the user interface has to deal with the problem, but if it can't establish there is a problem because it can't identify that the stored version is different to the current version of offset then how can the user interface even warn you there is a problem. It needs to ask if the versions match ... and it may be that it is dealing with a diary fom a third source so a centrally sourced reliable version of TZ is critical.
I still can't parse this (try again with smaller, shorter, sentences please?), but I think you may misunderstand the problem. The time and the zone must be stored, becuse whther the time shifts with DST is a function of the zone. As long as the calendar app stores some things like "9:00am US/Eastern" (for a dentist appointment) and "13:00 UTC" (for an international conference call), calendar apps should work well. --jhawk@mit.edu John Hawkinson