By law the Daylight Savings Time changeover dates were changed. The Calendar Server 6.3 software contains the new corrected timezone tables. All events and tasks created going forward will have the correct times. However, the preexisting events and tasks that fall between the old and new changeover dates will be off by one hour. This problem occurs twice for each year you have in your calendar, once for the Spring Standard Time to Daylight Savings Time changeover, and again when the Fall Daylight Savings Time to Standard Time changeover occurs.
This is the same problem as problem number 6502376 described in Reported Problems in Calendar Server 6.3 , later in this document.
Fix:The standard fix for this problem is to allow users to adjust the times for any events in their calendars that are effected.
There is a fix program that technical support can supply by request.