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Questions for Exchange 2016 to EXO
Hi, I have a few questions regarding a migration/transition to Exchange Online. I'm new to this environment but we are currently running Exchange 2016 and will deploy Exchange 2019 during the summe...
the Exchange Deployment Assistant is your friend here. A couple of points:
- autodiscover needs to point to on-prem Exchange if you have Outlook clients outside your corporate network connecting to on-prem mailboxes. If you don't have this scenario, then you can point autodiscover to EXO. So generally you wouldn't make this change until all mailboxes are migrated (EXO won't redirect Outlook clients back to on-prem Exchange, but Exchange on-prem will redirect to EXO)
- Once a mailbox is migrated, the Outlook client will generally be reconfigured to point to EXO (that's what autodiscover does), so there won't be any proxying for either internal or external
- To reduce any impacts, always migrate shared mailboxes (including calendar delegation) at the same time as users who have the delegate permissions. In theory an EXO mailbox can access an on-prem mailbox, depending on the permissions (and vice-versa), but we've always seen issues, so migrate them both so you can guarantee no issues (especially the critical ones)