Microsoft has changed the product service strategy for Exchange 2007. Details can be read at http http://support.microsoft.com/?kbid=937194, but the short story is that Microsoft will no longer produce traditional updates that you download and patch Exchange. The Update Rollups are more like service packs, where it's a complete reinstallation of the product with the patches incorporated. The web article above explains why this is an improvement and provides a more stable environment.
Now that we've all sipped the Kool-Aid, let me explain what this means in reality. Microsoft released Security Update for Exchange Server 2003 SP2 (KB931832), which is a critical security update that affects Exchange 2000, 2003 and 2007. The updates for E2K and E2K3 are 3.7MB. The Update Rollup 2 for E2K7 is 27-57MB, an increase of 730%-1,550% for the same patch. The size varies, depending on the roles installed. Keep in mind that you're going to have to download, distribute and deploy this to each E2K7 server, so plan your deployment and bandwidth accordingly.
A few other items of note:
- Deployment on an E2K3 server takes 2 minutes, stops and starts Exchange related services. Deployment on an E2K7 server takes 9 minutes and requires a server restart.
Computers running only the E2K7 management tools require the same 27-57MB update as a full Exchange server. In most environments, administrators load the Exchange management tools on their DCs to facilitate user provisioning. You must now be aware of DC unavailability caused by this issue.
- Updates that would normally not need a system restart in previous versions will need one in E2K7.
- You will no longer have the option of not deploying a specific update, since all Update Rollups are cumulative.
Security Update for Exchange Server 2003 SP2 (KB931832) can be downloaded via Windows Update or from here.