Based on the question and feedback from this forum thread, I've made a few modifications to the Dockerfile to fetch a new version of the Logitech software. I've also taken the liberty to turn a few separate RUN commands into one in a few spots, to keep the amount of layers down.
I haven't been able to test the resulting container as I don't have a squeezebox, but since the software is from an external source anyway I'll just go and assume it's good.

Hope this helps!