> I'm not sure that there is a big benefit for us to drop Windows 8 
> support (only Windows 8 but continue to support Windows 8.1), 
> compared to the annoyance for users.

According to statcounter.com and netmarketshare.com, Windows 8 still has 1% or less of the desktop market (across all platforms), while Windows 8.1 has about 5%. In comparison, Windows 7 has about 25-30% share, and Windows 10 has about 45-50%. I expect to see complaints about dropping Windows 7 support in 3.9. It's still quite popular and may take longer to die off than even Windows XP. I don't expect much noise, if any at all, about dropping Windows 8. Microsoft hasn't supported it for over 3 years.

A minor benefit of requiring Windows 8.1 would be support for process snapshotting (*). We could re-implement win32_getppid based on PssCaptureSnapshot and PssQuerySnapshot. This would only snapshot basic information about the current process (a few NtQueryInformationProcess system calls), whereas a Toolhelp snapshot, as is currently used, captures information about every process and thread in every session. Like I said, it's a minor benefit -- especially if we make the parent pid a static variable, so it only has to be looked up once. But this also opens up other features provided by this facility, including walking the handle table and virtual memory, if someone finds a use for them.

(*) For some reason ProcessSnapshot.h requires NTDDI_WIN8 instead NTDDI_WINBLUE, so this isn't actually a case for changing the value of  Py_NTDDI, but it should be in principle. The docs for process snapshotting require Windows 8.1, and the Windows 8 version of kernel32.dll (6.2.9200.*) does not export any of the Pss* functions, so it really was/is not available in Windows 8 as far as I can tell.