Author uses Python 2.2 and cracklib 2.7. Python 2.1 has been tested, it works as expected. Because of the simple interfaces being involved it is far from being impossible to build crack on top of older versions of both Python and cracklib.
Any suggestion or patch allowing the use with ancient versions is welcome. Reports of runs with older versions are welcome as well. The author will keep record of the oldest reported versions. Contest starts... now :)