I will update here any Dota Allstars 6.59 beta has been release. But i don't know about release date. The latest Dota Allstars map now is Dota Allstars v6.58b.w3x, you can download here.
Here is a quote from IceFrog:
Thanks to everyone that sent me bug reports for 6.58. I just released 6.58b after many countless hours of bug hunting. Let me know if I missed anything and what you want to see in 6.59. I will begin work on it after I wake up tomorrow morning, though I might sleep a little extra to make up for the last few nights :)