Willy had a question today...
"A customer got this e-mail about DST 2007 update - http://support.microsoft.com/kb/933360/en-us, which supersedes and replaces update KB931836, released in January 2007. Is this a mandatory update?"
It depends. This is an update for those customers who need the update for the added and revised countries (new time zone rules for Jordan and New Zealand, for example), replacing update KB 931836.
Per the KB... "Customers who have already deployed update KB 931836 should evaluate whether any of the five specific time zone changes that are addressed in the update described by this KB article merit deploying this update immediately. If systems are not directly affected, you can schedule deployment at the next available opportunity. We recommend that all customers standardize on the most current Windows cumulative time zone update to guarantee the consistency of the time zone database on all systems."