We currently have two exchange servers running 2003 R2 SP2 which replicate mailboxes using something called Lifekeeper. One exchange server is at site 1 and another at site 2 connected via a lease line.
We have now migrated to Exchange 2010 dedicated hosted solution. We have moved the schema version to 47, added 2008 DC's and the Exchange 2010 server and all mailboxes are migrating fine. Both sites have VPN's to the hosted network where the DC's and new exchange server reside.
Once all mailboxes are migrated what's considerations should I be thinking of to safely removing these exchange 2003 servers from our network?