All that said, if we're going to shell out to "ver", we may as well try "wmic os get Caption,Version /value" first and parse its output. For me, it looks like the below (with a number of blank lines around it):
Caption=Microsoft Windows 10 Enterprise
Version=10.0.19043
I would assume the output is in MBCS, and there doesn't appear to be an option to change that - the "/locale" option appears to influence translations, rather than encoding.
We'd still want the "ver" fallback I think. The wmic command is deprecated in favour of PowerShell commands, which means we would have to implement native calls to get equivalent functionality. But I expect neither cmd.exe nor wmic.exe will actually disappear for a long time.