I am in the middle of a migration from 2007 to 2013. I have a total of 300 mailboxes and have successfully moved about 50% of them so far.
I plan on leaving the 2007 server up and running for a couple of weeks without any mailboxes on it so users Outlook and Active Sync phones will automatically connect to the new 2013 server.
My question is can I begin the Public Folder Migration piece while the mailboxes are still moving to the new server, or do I need to wait until ALL mailboxes have been successfully migrated?
I have been using this walk through for the migration: