Hi,We're running a multi site CCR installation of Exchange 2007 SP1 entirely on W2008 servers.I've read up on the upgrade process including the CCR requirements and am happy with that. However, I'd like to know if there is a preferred order of upgrading the servers dependent on roles?Do I need all my CAS's and HUB servers upgraded before upgrading the mailstores or will this not be an issue?ThanksSoops

Yes there is a recommended order in which you'll want to upgrade. From the SP2 Release notes: We recommend that you upgrade your servers that are running the Mailbox server role after you upgrade your servers that are running the Client Access, Unified Messaging, Hub Transport, or Edge Transport server roles. Upgrade your computers in the following order: 1. Client Access servers 2. Unified Messaging servers 3. Hub Transport servers 4. Edge Transport servers 5. Mailbox servers Microsoft Exchange Server 2007 Service Pack 2 (SP2) Release Notes http://www.microsoft.com/downloads/details.aspx?FamilyID=ee7829a3-0ae8-44de-822c-908cd1034523&displaylang=en

Thanks Mike, exactly what I was looking for