I have read up on how Exchange 2007 no longer contains a RUS and 1. that the user is stamped when created 2. you can manually run update-emailaddresspolicy, but what do you do with your existing 2003 RUS? Should you turn it off? If so, what is the recommended method? It appears to continue to run onmy 2003 servers even after installing Exch 2007 in my org. Does it only affect users on 2003 servers? And if the policies are different yet affect users on Exch 2003 and 2007 servers, which one wins? I've been looking and I can't find something that addresses this question. Thanks!

Ultimately you delete the RUS objects when decommissioning E2K3 so leave them be for now and concentrate on moving all users to E2K7.

We have over 35,000 users currently on Exch2k3 with plans to add another 25,000. Coexistence will be a way of life for some time, and migrations may take a year or more. Should I just upgrade the default policy to 2007by executing the set-emailaddresspolicy task, and then manuallyrun the default policy from a 2007 EMS to stamp any users created in the 2003 environment?