Forest and domain functional level to Windows Server 2019


My permanent & home lab run 100% on Windows Server 2019 when it comes to infrastructure. AD, DNS, DHCP, 3rd party infra management servers (WiFi controllers, SMS Gateways, net monitoring tools, …). Why, well when it comes to practicing staying current & avoiding tech debt I practice what is preach. And I don’t need to have 20 analysts & management meetings to do so. What is need to know if whether it is supported, whether it works and that I know and understand the implication and benefits. One of the thing to test: raise forest and domain functional level to Windows Server 2019

Running Windows Server 2019 Active Directory

As I’m running Windows Server 2019 Active Directory for 100 percent all is ready to go. It’s a lab remember. A lab with backup actually. Yes, even my lab. So I am ready to pull the trigger. When I went to raise the forest and domain functional level to Windows Server 2019 (Insider build at the time or writing) I got  a little surprise:


Well, that’s a first! Why can’t I opt to raise the forest and domain functional level to Windows Server 2019? As it turns out it’s is just not there. Not yet and maybe not ever. Well the changes to the Active Directory schema were not huge to put it mildly. I went from 87 to 88 to in the permanent lab forest. It was a modest change.


That some kind of “functional “level don’t get raised has happened before. Not in AD, but in DFS for example in Windows Server 2016 you still run at Windows 2008 mode for the name spaces and that was a jump from Windows Server 2000 mode! As Windows Server 2019 has not yet gone RTM there is no way of knowing if the forest & domain functional level Windows Server 2019 will be there at that time.

Some might like this as it means there won’t be much application compatibility to worry about. Exchange is one of the most “delaying” factors in moving whole sale to newer AD versions. Sometimes they even change their minds (E2K10SP3 with RU’s & Windows Server 2016 AD was supported for about 3 months before it changed in the compatibility matrix on line). Some other AD integrating 3rd party software might also cause considerable delays.

On the other hand, sometimes I want to block older domain controllers form being installed. In dedicated & specifically managed AD environments where you want to avoid any deviation form this it’s a handy way of enforcing this. Anyway we’ll see how this ends up at RTM. Meanwhile we’ll keep an eye on the previews as I have 17554 to look forward soon to play with at night.

10 thoughts on “Forest and domain functional level to Windows Server 2019

  1. I’d love to have my lab on WS 2019 and that part is easy but I need to use System Center at the same time, otherwise testing is pointless.

    Is there System Center 2019 test media available somewhere?

      • Interesting, so no new Forest/Domain functional level remains 2016 even with Server 2019? I just finished upgrading from 2012 R2 to 2016 DCs – that means I am good for awhile 🙂 You write that the schema went from 87 to 88; this is done when you deploy the first Server 2019 OS or first Server 2019 DC?

  2. We are planning to upgrade our old server from windows 2008 standard to windows 2019 standard.

    We have 4 DCs – 2 running on windows 2012 R2 and 2 running windows 2008 R2 with domain functional level 2003.

    We would like to ask if we install a new windows 2019 standard (not DC) can we join into the domain with domain functional level 2003?

  3. Just ran across this as I had/saw the saw issue. from the link workingardinit posted it stays at 2016.

    Windows Server 2019
    There are no new forest or domain functional levels added in this release.

    The minimum requirement to add a Windows Server 2019 Domain Controller is a Windows Server 2008 functional level. The domain also has to use DFS-R as the engine to replicate SYSVOL

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