Why Is Python Changing?
As you may already know, Python is undergoing its most significant transformation since it was released in the early 1990s. Even the revision change from 1.x to 2.x in the fall of 2000 was relatively mild—Python 2.0 ran 1.5.2 software just fine back then. One of the main reasons for Python's stability over the years has been the steadfast determination of the core development team to preserve backward compatibility. Over the years, however, certain "sticky" flaws (that stick around from release to release) were identified by creator Guido van Rossum, Andrew Kuchling, and other users, making it clear that difficult changes were needed in order to ensure that the language evolved. Python 3.0 marks the first time that a Python interpreter has been released that deliberately breaks compatibility.
The changes aren't mind-boggling; you'll still recognize Python. The remainder of this article gives an overview of some of the big changes.