By now, we have a good understanding of how to prepare for, deploy, and start the process of migrating mailboxes. Before we get too far down the path of migrations, let's consider some additional changes that may be required to either support a complete move to Office 365 or a long-term coexistence strategy.
As we approach finalizing our migrations to Office 365, let's review some on-premises changes that may be necessary. These changes may include:
On-premises resources changes
Changing your MX record in a hybrid configuration