I’ve done some work on MMH 8, which so far has been separation of the code and user interface (untangle MMH from Windows) but I haven’t done anything since January.
My plan is to release MMH 8 (for Windows) and then build a UI for MacOS on top of that, for just a few tools initially which will be related to BDA/BDV audio conversion, tagging & renaming, chapter management/splitting and cue file creation. That will include the MusicBrainz database lookup to get album/concert tracks and other metadata online.
I will probably get back to MMH 8 fairly soon but I have a 6 week trip into the Northern Territory (outback) starting mid June so a Mac version won’t happen until late this year at earliest, after I’m back.