Managed Server Services now supported operating systems follow below table

OS  Major Version 
CentOS Server  6 , 7 and 8+
Red Hat Enterprise Linux Server  6 , 7 and 8+
Ubuntu Server  16.04 LTS , 18.04 LTS and 19.10+
Debian Server  8 , 9 and 10+
SUSE Linux Enterprise Server  12 and 15+
Windows Server   Windows Server 2012 Essentials 
Windows Server 2012 Standard 
Windows Server 2012 Datacenter 
Windows Server 2012 R2 Essentials 
Windows Server 2012 R2 Standard 
Windows Server 2012 R2 Datacenter 
Windows Server 2016 Essentials 
Windows Server 2016 Standard 
Windows Server 2016 Datacenter 
Windows Server 2019 Essentials 
Windows Server 2019 Standard 
Windows Server 2019 Datacenter