They don't use semantic versioning. Python 2.0 was compatible with Python 1.5. (...

chubot on Sept 17, 2014 | parent | context | favorite | on: Why Python 4.0 won’t be like Python 3.0

They don't use semantic versioning. Python 2.0 was compatible with Python 1.5. (There was a licensing change, but that doesn't mean anything in semantic versioning)