The December 2010 DST Cumulative Update for Windows operating systems focuses on the following changes :
o A new timezone has been created for Magadan. The Magadan timezone has support for Daylight Saving Time, with 2011 DST running from March to October.
o The existing timezone "(UTC +11:00) Magadan, Solomon Islands, New Caldonia" has been renamed "(UTC +11:00) Solomon Islands, New Caledonia". This is only a displayname update - the rules for this timezone have not changed. As before, this timezone does not have DST support.
Namibia: The offset has been changed from UTC +2:00 to UTC +1:00. In addition, for 2011 and forward, the DST start date will occur in September, and the DST end date will occur in April.
Egypt : the 2011 DST start date is set to occur in April and the DST end-date is set to occur in September. This is provided to address cases in which 2010 Fix-its for temporary DST changes were only partially applied.
In addition to these changes, the December DST CU contains 2011 adjusted DST start and end-dates for the following timezones:
For more information on these adjustments, refer to this Microsoft KnowledgeBase article: http://support.microsoft.com/kb/2443685