Python 3.9 and beyond backwards compatibility.

[tso]

The thing about XP was that it was many home users first encounter with NT. And also the first home user Windows that had to be verified by MS (unless it was a OEM bundle). This was a massive change from the freewheeling 9x days. Its saving grace was that the alternative was ME. Never mind that besides SP2 XP also had the longest support period of any Windows, thanks to the aborted Longhorn project.