You can upgrade the OS on a server to Windows Server $2016$ from:

Select one:

a$.$

You cannot upgrade server operating systems; they must be always be installed as a clean installation.

b$.$

$64-$bit versions of any version of Windows including Windows XP and newer

c$.$

$64-$bit versions of any version of Windows Server including Server $2008$ and newer

d$.$

Windows Server $2012$ or Windows Server $2012$ R$2$