KB979306 supersedes KB976098 and introduces a number of changes “This update includes additional time zone changes that were signed in to law after update 976098 was created,” Microsoft stated. “If you’ve already deployed update 976098, read descriptions of specific time zone changes that’re addressed in this article to determine whether you must deploy this update immediately. If systems aren’t directly affected, you can schedule deployment at next available opportunity.” In order to make sure that their copy of Windows displays time information currently and consistently with time zones worldwide, users need to deploy the update as soon as possible. Microsoft builds all DTS updates as cumulative update rollup packages. In this regard, users should know that the Feb 2010 cumulative time zone update for Windows operating systems (KB 979306) contains a variety of refreshes released previously including KB928388, KB929120, KB933360, KB942763, KB951072, KB955839, KB970653 and KB976098.
More info: KB979306