I can tell you that I installed El Capitan on my test Mac (2010 MacBook Pro) and everything worked for version 1.42. If you would like, I can install 1.5 and update my board to version 1.5 and test it (I’ve been meaning to update for a while).
I have done some testing and I have found that the GLD editor works on both OSX El Capitan as well as Windows 10 for both version 1.42 and version 1.5.