[Samba] Raisung domain Level on 4.14.4

[Mueller]

Hello,

I am running ,
[root at dom etc]# samba -V
Version 4.14.4

And  domain level show keep me telling it is only domain-level 2008R2????


[root at dom etc]# samba-tool domain level show
Domain and forest function level for domain 'DC=plk,DC=loc'

Forest function level: (Windows) 2008 R2
Domain function level: (Windows) 2008 R2
Lowest function level of a DC: (Windows) 2008 R2

I trieed to raise domain level with no success:


[root at dom etc]# samba-tool domain level raise --domain-level=2012_R2
ERROR: Domain function level can't be higher than the lowest function level
of a DC!

I thought samba 4.14.4 is about domain level 2012R2!?
How can I raise domain level?


Greetings 
Daniel