Informatica Why Python 4.0 won’t be like Python 3.0 15 Ottobre 2014 admin Newcomers to python-ideas occasionally make reference to the idea of “Python 4000” when proposing backwards incompatible changes that don’t offer a clear migration path from currently legal Python 3 code. After all, we allowed that kind of change for Python 3.0, so why wouldn’t we allow it for Python 4.0?