I have come into a situation where I need to deploy a new Exchange server at a small company. I haven't dealt with the newest version of Exchange (2010) yet, but am familiar with 2003 and 2007. The site is currently running one Exchange 2003 server, which hosts about 100 mailboxes. We have new hardware for an additional server, and this is where I need some advice.
Should I install Exchange 2010 on the new hardware and leave the older server as-is? Do I upgrade the old server and use it as a bridgehead or replication partner (there is nothing wrong with it other than it is a few years old and running Win2003/Exchange2003)? Can I leave the older 2003 server alone with only the POP mailboxes on it, and will it peacefully co-exist with the new server?
Any advice is very appreciated!