Update April 22:
Apparently I didn’t test this release as thoroughly as I should have, because it contained two serious bugs: clothes did not scale correctly when exported with units other than decimeters, and exported did not work at all with MH 1.0.2. Both bugs have now been fixed, both on bitbucket and in stable 0.26. The download link remains the same: https://www.dropbox.com/s/jrscejsv9uk8ch5/mhx2_stable_026.zip.
A new stable version 0.26 of MHX2 is available. It can be downloaded from here.
Compared to the previous version 0.25 a number of minor bugs have been corrected. The new version has been tested with Blender 2.74 and MakeHuman unstable.
For the past half year, I have worked very little on this project, so the unstable version of MHX2 has de facto just been a bug-fixed version of the stable build. This may change in the future, because I am really not very happy with the deformation properties and plan to redo the rigging at some point. As a result, the unstable version may become more experimental and buggy.