The case of disappearing Update Rollup 4
MSExchangeTeam blogged about the Rollup Update 4 that appeared for a short time in the Windows Update Site last week.
For a brief period of time on 9/9 (Tuesday), a pre-release version of Update Rollup 4 for Exchange Server 2007 Service Pack 1 (KB952580) was inadvertently made available to Microsoft Update, the Microsoft Update Catalog, and WSUS servers for download. While we quickly identified and removed the update from Microsoft Update within a short period of time, some servers using these distribution methods might have detected, downloaded and/or installed this version of the update.
Read more at source: http://msexchangeteam.com/archive/2008/09/11/449787.aspx