Thanks for your reply,
a customer is using NAV 2015 with CU2 on Windows Server 2012R2 and he wants (or has to) to move to Windows 2019.
His NAV is "extremely" customized... So such a big step to CU63 would be almost as big as to switch to BC14. But the customer can't upgrade at the moment or at least the next year.
I have to keep the object "merging" as small as possible...
After some testing I found out that CU10 is the first version where NAS services run.
Well, probably I'll go with CU12 because of the official statement that it "works" with Windows 10. I have a test system set up.
Best regards,
Cassidian