1
Wrong format for Daylight savings
Problem reported by Alexander Emmerson - 3/10/2023 at 4:39 AM
Submitted

Dear SmarterTools-Team,

invitations to other Clients (reproduced many times  with Lotus Notes) lead to wrong appointment times (one hour shifted; e.g. invited for 22:00 from smartermail and saved for 21:00 in Lotus Notes)

I guess the reason is the definition for the beginning of standard and of daylight which smartermail uses. 

For middle european time zone the daylight begins yearly at the last Sunday in March.
Smartermail uses  
RRULE:FREQ=YEARLY;BYDAY=5SU;BYMONTH=3 while others (e.g. outlook) use
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3

For middle european time zone the standard begins yearly at the last Sunday in October.
Smartermail users  
RRULE:FREQ=YEARLY;BYDAY=5SU;BYMONTH=10 while others use
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10

Here the relevant part of the VCALENDAR text: 

BEGIN:VTIMEZONE
TZID:Europe/Berlin
X-LIC-LOCATION:Europe/Berlin
BEGIN:STANDARD
DTSTART:00011104T030000
RRULE:FREQ=YEARLY;BYDAY=5SU;BYMONTH=10
TZNAME:Mitteleuropäische Zeit
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:00010405T020000
RRULE:FREQ=YEARLY;BYDAY=5SU;BYMONTH=3
TZNAME:Mitteleuropäische Sommerzeit
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
END:DAYLIGHT
END:VTIMEZONE

Sorry for posting this in an already closed thread before.

Best regards

Reply to Thread