I am running a single 2010 Exchange server in my environment. A couple of months ago it got a bug I couldnt clean so I decided to build another server to replace it. Everything went fine, ie, moving the CAS, hub, and Internet mail roles etc but I did have a small issue that I discovered after moving the mailboxes and that was even though I created new DB's on the new server, the DB's showed the RPCClientAccessServer attribute still pointed to the old server. I ran a PS command and changed the new DB's to the new server. OWA, Outlook AnyWhere and ActiveSync work fine. Autodiscovery seems to work fine because when I create a new profile in Outlook, it finds the new server rather than the older one.
The problem I have is that not all existing Outlook clients are pointing to the new server in their existing Outlook profile as I soon figured out when I diasabled the NIC on the old server to make sure it wasnt still being called upon to do work. I would say it's about half of my clients that updated with the new server vs one's that did not. I can create a new profile but I would rather not if I didnt have to do so as we have about 500 clients across multiple cities.