Found an old post via Google:

Windows 10 returns same Win Version (6.02) as Windows 8.1 (Using VFP OS() function) https://social.msdn.microsoft.com/Forums/en-US/ba6983f6-c864-4051-9495-9e2ce... On Thu, Nov 15, 2018 at 1:50 PM mbsoftwaresolutions@mbsoftwaresolutions.com wrote:

VFP9SP2

According to http://fox.wikis.com/wc.dll?Wiki~VFPFunctionOS, it looks like 8 and 10 return the same values?

Windows 7 Windows 6.01 OS(5) returns "7600" AND OS(11) returns "1" Windows 7 SP1 Windows 6.01 OS(5) returns "7601" AND OS(11) returns "1" Windows 8 Dev Preview Windows 6.02 OS(5) returns "8102" AND OS(11) returns "1"

Windows 8 (Release) Windows 6.02 OS(5) returns "9200" AND OS(11) returns "1" Windows 8.1 Windows 6.02 OS(5) returns "9200" (why not 9600?) AND OS(11) returns "1" Windows 10 Windows 6.02 OS(5) returns "9200" AND OS(11) returns "1"

[excessive quoting removed by server]