Do versions 2.79 and below no longer work?

[DG3Ds]

I've tried installing the addon in Blender versions 2.79 and 2.78 in various ways, but I always end up getting this error

[niacdoial]

oh yeah, that's because the way you need to declare a blender add-on to blender changed with blender 2.80.
...and the syntax involved is simply not supported by the version of python blender 2.7x uses.

I made a new branch to backport some of the newer stuff to blender 2.7x
(just... know that I've only tried blender 2.79b, and for some reason my system really doesn't like versions of blender that old. it crashes whenever I right-click in a viewport that contains an armature)
Anywho, please tell me if it works for you!