The QT version compiles as a desktop app as well. It uses an HTTP api to the coffee machine. Normally only localhost, but for development I can tunnel that port over ssh, so from my desktop I can use "actual" hardware. Same with Flash/Gnash, ssh tunnel and a local instance (recently made a snap for that: https://raymii.org/s/blog/Ive_packaged_up_Gnash_as_a_Snap_fo...).

But thanks for the tip, I'm going to try that and see how it works. Maybe even get the old machine running the new UI via vnc.