[Ietf-calsify] Time Zone Rule Changeover
caleb at everyone.net
Thu Jun 22 18:38:28 PDT 2006
This question concerns the switch from standard time to daylight savings
time in the United States that will occur on March 11, 2007.
From what I understand most versions of Outlook (and some other CUAs)
can only process VTIMEZONE observances with at most one RRULE property.
This has led most Olson database converters to discard all historical
data and only use the most recent recurrence rule for each observance
(if there are any).
The switchover on March 11, 2007 will be the first that uses a new time
zone recurrence rule standardized by the Energy Policy Act of 2005. The
previous rule would have required a switchover on April 1, 2007.
Which recurrence rule should I use?
If I use the old rule then recurring events that are still happening
next spring will be 1 hour off for that window and for a similar window
If I use the new rule then my events will be 1 hour off during a similar
window this fall.
Has anyone come up with a solution to this problem? I realize that many
CUAs (including mine) will look at the TZID parameter and try to use
their own strict time zone definitions before parsing the included one,
but I feel that this is a serious problem regardless.
This VTIMEZONE definition uses the new recurrence rule:
This VTIMEZONE definition uses the old recurrence rule.
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