We are replacing all Exchange 2003 (3 servers) to 1 Exchange 2007. We have 3 sites with Unity 4.2 servers (each site has 2 servers w/failover). All users are currently and will be in the same AD and forest and all mailbox will be moved to Exchange 2007.
When we upgrade to Unity 7.0, what steps should we take when changing the partner Exchange server to 2007? Should we change it during Unity upgrade or wait until after the upgrade?
What possible issues may arise with what we are trying to do in relation to Unity upgrade and Exchange migration?
Any information you can provide is appreciated.