I am currently upgrading domain controllers from 2008 R2 (2 of them) to 2019, and have already promoted and setup 2 new ones. Domain and Forest level is still set to 2008 R2. All FSMO roles have been transferred and Exchange 2010 successfully picked up and using see the new 2 2019 DCs.
Now Microsoft's site says it does not support 2019 environment? This is the part that concerns me, because it clearly does.
I haven't demoted 2 old DCs yet, but based on all info I could find Exchange is already using 2019 DCs.
Also all flags look proper in Exchange Discovery event viewer (event 2080)
Process STORE.EXE (PID=5108). Exchange Active Directory Provider has discovered the following servers with the following characteristics: (Server name | Roles | Enabled | Reachability | Synchronized | GC capable | PDC | SACL right | Critical Data | Netlogon | OS Version) In-site:
CDG 1 7 7 1 0 1 1 7 1 for both new 2019 DCs.
Should I be concerned with demoting 2 old ones? Based on the matrix Exchange 2010 should work with 2016 functional level, so if I were to raise it to that level after demoting the old ones everything should still be OK?
Is there another test I can run to make sure exchange will still be fine after demoting old ones?
I was thinking explicitly excluding 2 old ones using -StaticExcludedDomainControllers on the exchange to make sure its not using them at all? Will that be sufficient to make sure?
I have attached a screenshot from exchange console with more info.
It would be nice to find why Microsoft is saying that Exchange 2010 is not able to communicate with 2019 DCs...
The document does not outline what appears to work or not work but instead documents what has been tested and is currently supported. If it's working for you then that's a good sign but if some problems arise it simply is not a supportable configuration. The risks / burden of support is left to end user.