We have a 2003 SP2 server that is both a domain controller and running Exchange 2003. We're in the process of moving away from this configuration and I wanted to confirm that it's ok to remove the FSMO roles from this server. Right now it holds 4 of the 5 (all but naming master).
Our plan is to move all the FSMO roles off the server, make sure we meet the pre-req's for Exchange 2010, bring in Exchange 2010 on a 2008 R2 server in co-existence mode and then decommission Exchange 2003 after the transition. Once this is done we'll ultimately demote the 2003 domain controller as well, but for the time being we'd like to get the FSMO roles off.
I've done a fair bit of searching and haven't found a definitive answer to this, I know Exchange 2003 behaves a little differently if it's installed on a 2003 DC which is why I wanted to confirm.