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I upgraded out Domain Controllers and Servers from Windows Server 2008 R2 to Windows Server 2016 via Windows Server 2012. Before the process of each jump:

From Windows Server 2008 R2 to Windows Server 2012 R2 From Windows Server 2012 R2 to Windows Server 2016

I successfully ran /forestprep & /domainprep without an issue on both Domain Controllers.

After the upgrades I went over to my Active Directory to check the functional level and it still says Windows Server 2008 R2.

Why would this be? I am upgrading all my Windows 7 machines to Windows 10. I have a few machines still running Windows 7 Embedded but I don't think that would effect the level. I am a little confused. Do I need to now upgrade the Domain Funcational level once more now that the upgrade is complete?

JukEboX
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Domain (and Forest) functional levels are never automatically upgraded. Upgrading OSes and prepping the schema with newer versions just gives you the option to do so.

Also, the DFL/FFL setting has no bearing on client compatibility, only domain controllers. It's simply a mechanism to allow you to enable newer AD features.

The Forest and Domain Functional Levels doc explains in a bit more detail. But here's the important bit:

Functional levels determine the available Active Directory Domain Services (AD DS) domain or forest capabilities. They also determine which Windows Server operating systems you can run on domain controllers in the domain or forest. However, functional levels do not affect which operating systems you can run on workstations and member servers that are joined to the domain or forest.

Ryan Bolger
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  • That is understandable. So I guess my question is will it always be at Server 2008 R2 level even though both DCs are at server 2016? – JukEboX Jun 21 '19 at 18:00
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    The Domain Functional Level will stay at whatever it's currently at until you decide to raise it. If your domain is the only one in the forest, don't forget to upgrade the Forest Functional Level as well. – Ryan Bolger Jun 21 '19 at 19:35
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After the upgrades I went over to my Active Directory to check the functional level and it still says Windows Server 2008 R2.

The Domain and Forest functional levels aren't raised simply by installing Domain Controllers of a later OS version. You need to specifically and directly raise both.

You can raise both to whatever level is supported by your Domain Controllers.

joeqwerty
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