http://abrok.eu/stockfish/
a new version is here
>>>
https://www.chess2u.com/t6930-the-best-of-the-best-rating-list-the-ultimate-world-s-best-engine-matches
at the bottom of the page (from the above link)
I attached the rating list
which shows that
this new stockfish which was released on
2013 March 4th
is a lot stronger than stockfish 2.31