I have this version working on test.webwork.maa.org but you will need to do a bit of work on the configuration files when you install it, so plan to spend a little time, and don't risk it on a machine where being down for a few hours would be a disaster.
You can use svn to get the latest version from github.com/openwebwork
For instructions of using svn with github go to
http://webwork.maa.org/wiki/Github#Download_WeBWorK_via_svn_to_an_svn_repository
the instructions are pretty straightforward.
There is a README in the webwork2/conf directory for working with the new configuration files.
It's best to get new versions of both the webwork2 repository and the pg repository from github.com/openwebwork.
Complete docs still need to be written which is part of why the newest version hasn't been pushed to the svn repository yet. (Exam season is the other reason :-) )
--Mike