Hi @verycd, The AppImage should work on Linux Mint but I have not tested it. Please can you post the error messages that you get. Please start the App image from the command line and then post the error messages that you get here.
It is quite normal for distros to be quite a bit behind with app versions. However the advantage with linux is it is easy to compile the code for source, just follow these instructions.
https://github.com/pianobooster/PianoBooster/blob/develop/BUILD.mdPlease let us know if that worked for you and please don't forget to post here the App image error you are getting.
L.