I made my first attempt at migrating from 2007 to 2013 but ran into some problems. My 2013 CAS and MB servers are successfully installed along with their prerequisites (AD entries, external and internal DNS is active or ready to be, FW rules etc..). I'm at this point here in the Microsoft plan..
http://technet.microsoft.com/en-US/exdeploy2013/PrintChecklist?state=2284-W-CQCkAgIAQACACEEAAQAAAA~~
"Perform the switch over"
My questions are about behavior.
1. When I have everything setup correctly and DNS and the SCP's changed, the Webmail OWA site for all users will be the 2013 login interface, and after logging in will my 2007 users then see the 2007 OWA interface on my old CAS?, or will they access their 2007 MB using the 2013 interface?
2. There is a "backend imap4" service on my 2013 servers. We will still have some 2007 mapi connected MB clients. Do I need these services started to hand off 2007 mapi requests to the 2007 portion of the environment?