I just uploaded the first beta release for Cython 0.20, it's tagged as 0.20b1 in the git repository or you can find it at http://cython.org/release/Cython-0.20b1.tar.gz . A summary of the changes can be found at https://github.com/cython/cython/blob/0.20b1/CHANGES.rst , please try it out and let us know if you have any issues. - Robert