According to Microsoft, Exchange 2013 (highest CU) isn't compatible with a domain controller level of 2019. At least if I'm reading this matrix correctly:


With a 2012R2 domain currently, if I build a 2019 server and promote it to domain controller. Will this cause issues immediately or only if the domain/forest functional levels are upped?

I wouldn't immediately raise the domain/forest functional levels. If this works, I would be on 2012R2 domain/forest functional with 2019 domain controllers in the hybrid domain setup, until our Exchange environment is migrated and then we can up our domain/forest functional levels.

I'm thinking I will have to either migrate Exchange 2013 to either 2019/Exchange Online first, then we can build our new domain controllers and continue the migration.

  • No-one knows if there will be issues due to ES 2013 was not tested with AD 2019 servers, and no-one uses that platform configuration. There's very little difference in AD 2016/2019, however if you are running something that is not on the supported matrix you own that. Microsoft can say the configuration is not supported. This is about the servers, and not the forest/domain level.
    – Greg Askew
    Jul 18, 2022 at 17:38

1 Answer 1


If you don't need any features/functions that Windows Server 2019 brings, then leave your Domain Controllers as is until you complete your migration. Once the migration is complete you'll need to determine how you're going to manage Exchange attributes for your on premises objects synced to Office 365 and take appropriate steps. (ADSIEdit, Exchange Server 2019, or this https://practical365.com/removing-the-last-exchange-server and this https://docs.microsoft.com/en-gb/Exchange/manage-hybrid-exchange-recipients-with-management-tools).

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .