Python 2.5.1 was released on April 18th, 2007.

This is the first bugfix release of Python 2.5. Python 2.5 is now in bugfix-only mode; no new features are being added. According to the release notes, over 150 bugs and patches have been squished since Python 2.5, including a fair number in the new AST compiler (an internal implementation detail of the Python interpreter).

http://www.python.org/download/releases/2.5.1/