Current solution: Unity 3.1.3 with Exchange 5.5 (on separate box), Unified messaging, and 2003 Active Directory.
We want to upgrade to Exchange 2003 but I found out that this will break Unity if we don't upgrade to 4.x first.
My plan is to first upgrade Unity to 4.0.4 with the existing Exch 5.5. Then later we will migrate to Exch 2003 - my question is about the Domain/Forest Prep process. Do I need to run the Unity Domain Prep tools now? Or can I wait until I am about to install Exchange 2003? Can someone tell me the best precedure?