Starting in the spring of 2007, Daylight Saving Time (DST) start and end dates for the United States will transition to comply with the Energy Policy Act of 2005. DST dates in the United States will start three weeks earlier (2:00 A.M. on the second Sunday in March) and will end one week later (2:00 A.M. on the first Sunday in November).

This update includes the changes for the United States DST change for the components affected in Microsoft Exchange. It also includes changes for the time zones in Canada which will make the same change to their DST transition dates from 2007.

Additionally this update includes changes to time zone behavior and DST settings that have taken place since Exchange Server 2003 was originally released. These changes were previously released as individual updates and documented in articles in the Microsoft Knowledge Base.

This version is only intended for use in testing environments. A final version of this update for production deployment will be released in January 2007 through Microsoft Customer Support Services (CSS), Microsoft Download Center, and Microsoft Update.