Latest version of Musescore doesn't work with two accordions

I have just downloaded and installed the latest version of Musescore. Previously, since Musescore playback does not provide functionality to adjust the volume of the Left Hand and Right hand for accordion independently, I have used two accordions, and turned the left hand off on the Primary, and turned the right hand off on the Secondary. Since I have installed the latest version of Musescore, the second accordion does not play in playback. Can you have somebody look into this please? And can you let me know how I download the previous version of Musescore, so I can roll back to the last version that works please?
Thanks...
Dave Christie.