I am migrating our institutes Calendar for last 5 years for everyone from OpenGroupware to Zimbra. I have noticed some errors relating to the daylight saving time. Before 2007 the daylight saving time started at the first Sunday in April and ended at the last Sunday in October. From this year it starts at second Sunday in March and ends at first Sunday in November. So all our calendar events prior 2007 were shifted forward 1 hour in last week of October and backward 1 hour in the last 2 or 3 weeks in March. This error does NOT happen in windows OS but on both Linux and Mac OSs. So we concluded that the error is platform related. Update Linux and Mac did not solve the problem for us.

Have anyone noticed this? How can I correct the error? I am using perl/Soap to migrate the calendars.

Thanks in advance,