December 2009 cumulative time zone update for Microsoft Windows operating systems
Important This update supersedes and replaces update 970653, which was released in August 2009. This update also includes additional time zone changes that were signed in to law after update 970653 was created.
If you have already deployed update 970653, read the descriptions of the specific time zone changes that are addressed in this article to determine whether you must deploy this update immediately. If systems are not directly affected, you can schedule deployment at the next available opportunity.
We recommend that you deploy the most current Windows cumulative time zone update to guarantee the consistency of the time zone database on all systems.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB976098.