Can I raise the domain level of a Windows 2012 R2 to 2016 without upgrading the OS?

Question

I have an azure server that is a DC running 2022 - it is brand new - no previous domain. I'd like to join it to an existing domain however the existing domain is 2012 R2 - and and 2012 R2 level. I'm not sure the process for upgrading the 2012R2 domain level to 2016. Seems like I did this ages ago with 2012 using powershell but that was a decade ago and I may be completely wrong.

Answer 1

Hello,

Unfortunately, there is no option to upgrade a functional level unless the PDC (all DCs recommended) is upgraded to at least the same OS version as the DFL. In-Place upgrade is never recommended, as the recommendation from Microsoft is to promote a new DC, migrate all the roles into it, then raise functional level.

You can read more about the process and supportability at the official article: https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/deploy/upgrade-domain-controllers

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Answer 2

Thank you for asking this question on the Microsoft Q&A Platform.

I understand that you require to join a Windows Server 2022 in a forest with functional level 2012 R2.

You can use the functional Level 2012 R2 on Windows Server 2022

More info: https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels#windows-server-2012-r2-functional-levels

So, you can join your Windows Server 2022 in your forest and domains with functional level 2012 R2

About if you can raise the functional level of a Windows Server 2012 R2 to functional level 2016, the short answer is no.

More info: https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels#windows-server-2016-functional-levels

Hope this helps!

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