We've got 5 Exchange 2013 mailbox servers in a DAG. However, we've still got 2x 2007 mailbox servers and 2x 2007 Client Access/Hub servers. All migrations of live users are now finished.
A lot of old users were not migrated and left on 2007. Plan is to keep 2007 for the time being in case access is needed to these old mailboxes.
In the meantime, is there a best practice guide for to finally get rid of 2007? Ideally, as I've said, we'd like to disable but keep the servers for now. Also, what do we need to consider before doing anything? (One thing I thought of is applications sending email directly to 2007 servers)
I wasn't around when 2013 was added to 2007. Are they somehow "linked" now and does this need to be removed?