I have Postfix/Dovecot/Mysql on Centos 7 with mail_version = 3.2.4 setup new server same hostname as old server with mail_version = 3.3.3 using same hostname as old server
the thought was to change A records to point mailserver hostname to new server IP at switch over time is that an OK idea ? what do I then need to set the old server to forward all mail to new server ?