>>>Can anyone tell me what ?OS() returns under Windows 3.1 and/or 3.11?
>>>
>>>I only have Windows 95B and under that it returns DOS 07.10.
>>
>>AFAIK, OS() will only return the underlying operating system, therefore it will return whatever version of DOS is running. OS(1) will return the Windows Version. Win 3.x will return "Windows 3.x", Win95 returns "Windows 4.x" and NT returns "Windows NT".
>
>My Windows 95B returns "Windows 3.95" from OS(1), so it must only be Windows 98 that returns "Windows 4.x"?

No, my Win95 returns "Windows 4.00". According to Windows, it's Windows 95 4.00.950a