Hello,
i have a server running cpanel and dovecot currently.
i was wondering if the scenario below would work:

1- Create a backup MX record for my domain, pointing to the new server which is not active yet.
2- Install zimbra on the new server(block the ports so as to make sure no emails come in or out, and the primary MX records pointing to my current server works)
3- After configuring users accounts, i can take down my primary MX records and test. if things are ok will keep it that way, if not, will go back to the primary MX (old server).

Thanks