Im currently doing a migration of several users to O365, Ive changed all the DNS records apart from the MX records, however cannot add users alias's until I complete the DNS record, which I dont want to do until we are ready to migrate.
Can I ignore the MX record warnings and then add the alias, then when ready to migrate change the MX records? From my understanding users who send to my users on O365 external to my account O365 will still use the MX records and the emails will goto the current MX record destination. Is that right? This means they can continue to send and recive emails on the old system until I flick the switch and change the MX records, then all the users and alias's are already setup.