there is some small issue about the name of the package.
"open-stage-control-1.21.0-amd64.deb" should be "open-stage-control_1.21.0_amd64.deb"
with underscore between name_version_architecture + .deb
I say that to qualify the standards of debian packages
Thanks a lot for your work.
Thanks for the input, I'll change that.