I understand that you cannot co-exist or migrate to Exchange 2013 from 2003. My question is can I install Exchange 2013 in the same domain and just export/import PST files to 2013 as this is a small company of about 12 users with no public folders.
And when ready, change the firewall config and spam server to the new ip address of exchange 2013. Down time will not be an issue. As opposed to co-existing, this would be a server that is configured with no mailboxes until I import the PST.
I really do not want to upgrade to 2010 and then upgrade again to 2013.