A common first move.
WHAT TO PLAN
Which accounts move Whether historic mail moves When the switch happens What the fallback is
WHAT TO PREPARE
The new accounts, created and tested Historic mail imported, if required Devices ready to reconfigure
WHAT TO RECORD BEFORE CHANGING ANYTHING
Every existing DNS record.
WHAT CHANGES
MX records, directing mail to the new service.
WHAT ELSE MUST BE UPDATED
Mail authentication records for the new service.
Without them, mail from the new service fails authentication.
WHEN TO SWITCH
Outside business hours, with time to verify.
WHAT TO EXPECT
A period where mail may arrive at either service, while caches expire.
WHAT TO TEST AFTERWARDS
Sending and receiving, to and from external addresses Every device reconfigured That nothing is still delivering to the old service
WHAT TO KEEP
The old mailboxes, for a period.
WHAT NOT TO DO
Close the old service immediately.