[Dovecot] migration advice

Hi,

I am preparing a migration from courier-imap to dovecot. The maildir is in each user's home directory, and /home is mounted by NFS. All this running in a kvm virtual machine.

My plan would be to create a new virtual machine (with another IP) with dovecot, mounting the same /home, and switching a couple of users to dovecot for testing purpose. If the tests go well, I would then migrate the other users and assign the IP address of the courier imap kvm to the dovecote kvm.

Does that make sense? Or can it be problematic to have some users switched to dovecot while their maildir directory is still accessible to courier-imap?

Looking forward to reading your feedback, thanks in advance!

Raph