I tried to do apt-get upgrade, but python wouldn't upgrade itself. I get this: The following packages will be upgraded python python2.3 2 upgraded, 0 newly installed, 0 to remove and 1 not ...

Python developers made the decision to upgrade to the 3.x line, which is incompatible with the 2.x line, because developers sought to make some changes more dramatic than a typical upgrade while ...

That problem is compounded by developers who created dependencies or software libraries with Python 2, which in turn prevent developers downstream from upgrading to Python version 3.

Python 3.0, a new version of the language released earlier this week, has incompatibilities with the 2.x line, according to the Python Software Foundation.