I currently have an NT domain with one of the member servers running exchange server 5.5. I recently bought a new server with 2003 server. Currently it is a member of the NT domain, but I will be making it the new DC and retiring the old NT PDC. Will my nt member with exchange 5.5 still work after the domain upgrade? I will eventually upgrade to exchange 2003, but not for a while. I don't want to go ahead with the domain upgrade if exchage no longer works. Thanks.