There's huge difference between a point release 2.6 to 2.7 and full release 1.9 to 2.0 Most of Python's features are carefully crafted to not cause compatibili

There's huge difference between a point release 2.6 to 2.7 and full release 1.9 to 2.0 Most of Python's features are carefully crafted to not cause compatibility issues. 3.x is the major exception in many, many years.