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Hello
I'm in the middle of a migration for Exchange 2010 to Office 365. Once the mailboxes are migrated and I am ready to decommission the Exchange 2010, do I still need a new Hybrid server on prem to manage the mailboxes?
Depends.
Are you using AADConnect or ADFS? If so then, yes to be supported you have to have at least one on-prem Exch Server ( this will hopefully not be the case one day)
So what are the oder of steps once all mailboxes are migrated to Office 365.
1) Decommission Exchange 2010 servers
2) Standup Exchange Hybrid 2016 server?
I would do 2 then 1.
Make sure things are working after running the Hybrid Wizard on the 2016 server and set the endpoints to only the 2016 server.
Then decommission the 2010 servers.
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Hi @KashifRashid-5415 , agree with Andy suggests.
If you use AAD sync, your synced online users can only be managed within on-premise AD, as a result, it is necessary to keep an on-premise Exchange server to manage user’s mailbox. Like the Scenario two in the official document.
And if you have all of the mailboxes in Exchange Online and do not need to manage users from on-premises and no longer have a need for directory synchronization or password synchronization. You can safely disable directory synchronization and remove Exchange from the on-premises environment. Just like Scenario one introducees
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