Arasan 10.4 is available from http://www.arasanchess.org.
This is not exactly the version that played in the recent WCRCC tourney, but it is close to it.
Changes in Arasan 10.4:
1) Speedup illegal move detection in search.
2) Speedups in move generation.
3) Improved move ordering for check evasions.
4) Use IID more sparingly.
5) Several scoring changes, esp. fixes/improvements to material scoring.
6) Fix to "bk" command (to list opening book moves).
7) Time usage fixes/improvements.
8) A couple of locking fixes for more stable SMP operation.
9) Fix for invalid moves propagated to pv list
10) Clear history data before each search in testsuite mode.
Plus open book additions/fixes, as usual.
--Jon