Moratorium for Python 3
Guido von Rossum, author of the Python programming language, has proposed freezing the grammar and semantics of the language for a "period of several years". By doing so, von Rossum is hoping to facilitate the move from Python 2 to Python 3.
He suggests that frequent changes to the language are both a problem for alternative implementations, such as Jython and IronPython, and offer no benefit to users, who are frequently committed to using older versions of Python for an extended period. One year after the release of Python 3.0 , the vast majority of Python applications and frameworks are still based on Python 2.x.
Von Rossum expressly excludes the standard library from the moratorium. Changes to the Python interpreter itself (CPython) would also continue to be permitted.