rsync mail directory after migration?

We're planning a migration from one hosting provider to another, both using cPanel. We're going to backup each account, copy across to the new server and restore. After restoration we'll change the MX records on the old server to point to the new server.

The only problem is what happens with email arriving while backup, copy and restore are happening.

Can I simply use rsync to update the new server with any late arriving emails after making the MX record change? E.g.

Code:

rsync cpaccount@oldserverip.com:~/mail/ cpaccount@newserverip.com:~/mail/

Are there requirements here? E.g. both servers need to run courier or both dovecot? Same versions? How do I tell? Are there any permissions issues I need to deal with?

 

Is there a reason for this? I've seen other posts mentioning that rsyncing just ~/mail will work.