So Firehammer Audio originally did loop points with a hacky workaround(involving adding a buffer of the beginning of the loop to the end of the sound). This was the only good way I could get loops working.
Now, since GM actually can do loop points the right way, without the hack involved, I converted FHAudio to using it instead. It's all internal as far as the changes go(except it uses seconds instead of milliseconds since that's used by GM's functions).
As far as changes go, you may be able to use the system in the later LTS versions if it has the loop point function(and I think it does). You would have to re-author your music without the hack(optimally but not necessarily). And your sound definition calls would need to use the new fhfx naming ones, though if you put them all into a single place it wouldn't be too hard to fix. And the functions for actually playing sounds were left alone(only renaming arguments which doesn't affect the code calling them).
Feel free to hit me up on the Discord for help or more questions if upgrading interests you.