Yes, the mag release. In this iteration, the lever moves downward whereas the 1st & possibly the 2nd batch it moves upward. This was done for left handed shooters. I kind of like it out of the way in the new version, but hard to tell if it might be a bit cumbersome to unlatch the mag with the lever located in a fairly tight spot between the gauge and mag.
Also, to the best of my knowledge, those of us in the 1st run never got the barrel adapter that was supposed to be included to facilitate the use of a mod.
I completely dislike the new pseudo carbon fiber pattern.
Someone on the board here said (paraphrase) that one of the Huben moderator's sucks and apparently does little to nothing to tame the db's. FD, I'm just repeating what I read and don't personally know this for fact, but his assessment seemed genuine and honest.