It's live: How to address daylight saving time by using the Exchange Calendar Update Tool http://support.microsoft.com/default.aspx?scid=kb;en-us;930879 And the tool: Exchange Calendar Update Tool http://www.microsoft.com/downloads/details.aspx?FamilyId=A9336886-4B28-4 010-9416-36D38429438D&displaylang=en