Load files created with MuseScore 4 in MuseScore 3

This plugin allows you to load a file created with Musescore4 with the Musescore3 version. This is a simple replacement of the header of the different file types, to "trick" the software and force it to load the file anyway. You must first export the file created with Musescore 4 in .mscx format (uncompressed) and then load it into the plugin installed in Musescore 3: the file is automatically modified and saved with a slightly different name in the same folder. At this point it can be loaded from Musescore 3: not all the formatting and data present are preserved (but most do), but the notes will certainly be displayed. I won't dwell on the obvious and enormous difficulties of creating a more precise version, which goes beyond my interests. It works with Linux and Windows: any adaptation to macOS can only be done by users of this system. I created this plugin more for fun than for real needs (there is always the possibility of exporting to musicXML format), and I tested its effectiveness with only a few files (single instrument, multiple instruments, with fingering, with VSTi); Any users will let me know of any problems. Have fun.

A more complete import of MuseScore 4 files, keeping most of the style settings, can be achieved by using MuseScore 3.7 Evolution, see https://github.com/Jojo-Schmitz/MuseScore/wiki