Exchange 2016 out of office not updating
Several of my clients have opted to move toward this configuration, until Microsoft figures out a way to get rid of Exchange servers on-prem for good, while still keeping Directory Synchronization (or maybe we’ll just move AD/DNS to the cloud too…).
The main thing you should do here is identify what you have now, what you are moving to, and where everything is going to live at the end of the day.
For Coexistence and interoperability between Exchange 20, these values all need to be changed. NOTE: It should go without saying, but the certificate on the Exchange 2007 server should have been replaced by this time with a certificate that contains legacy.If you still have Dir Sync, you’ll need to upgrade it to Azure AD Connect.