Hi @John Bamba
I would appreciate it if someone could show me how to get around this. Should I drop the 2008 R2? will it raise it automatically to the 2012 R2?
If you want raise the functional level to Windows 2012 R2 you have to demoate the domain controller 2008 R2.
If you want raise the functional level to Windows 2016 , you have to demote DC 2008 R2 and DC 2012 R2.
The domain functional level cannot be higher than the Operating System version of all domain controller in domain.
The Forest functional level cannot be higher than the Operating System version of a all domain controller in the forest
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