I do not use MS. And so I am not really close to the needs for an AD.
But there are a old DSfW (OES2015SP1) as a PDC and a newer ADC (OES2018SP1). Now I want to eliminate the old DSfW-Host (OES2015SP1).
I have installed OES2018SP1 on a new host. But when I try to configure DSfW (New Domain Controller in an existing Domain Services for Windows Domain) I get a message that the first root domain controller has to be the same version as the ADC.
Now I found two questions:
a) How I get the PDC role from the old DSfW-Host to the new one?
b) Why I was able to add the existing ADC (OES2018SP1)?