I've got two 2003 servers running Sp1, it's way past time to upgrade to SP2. I notice from the release notes it says:
It may seem a minor point, but is there a recommended maximum time between upgrading the front end server and the back end server. I obviously don't want to leave it too long but may need to be overnight with the front end at SP2 and the back end at SP1 ?
Upgrade All Exchange Server 2003 Front-End Servers before Upgrading Exchange Server 2003 Back-End Servers