Hi @SF-6505 •
What is the impact if we migrate our Windows 2012 domain controllers to Windows 2019 on Azure adconnect?
There is no impact, domain controllers windows 2019 are supported by Entra Connect (Azure ad connect).
We also want to increase the functional level to Windows 2019
It's not possible , if you upgrade all your domain controller to Windows 2019 , the highest functional level is Windows 2016.
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