Just one simple question. Are there any insights on a new version for Win Server 2016 because the evaluation version is already in place and - of course - I get an error message when I try to install that my operating system isn't supported
Correct, as Niels stated it will be supported in the next version of Endpoint which will be renamed to Veeam Agent for Windows. I do know (you can search the forums here...) that there are some people that figured out a way to "disable" the OS check and got it installed on technical previews of Windows Server 2016. Some with success, others with failures (if I recall correctly, there are failures in the bare metal recovery).
But that won't be supported by us so if you plan to do this because you need protection already, do a few tests first (like can you recover files if necessary) and I really would advise against using it on a production box