I have a Mac Mini that is used primarily for Indigo Server. I recently made a huge mistake and upgraded the Mini to High Sierra. Of course the usb connection to my 2413U modem stopped working. I was able to get it working again by connecting the modem to the Mini through a USB hub. That worked for several months but last night it stopped and I wasn't able to restore comms. I'm currently running Indigo Server on another desktop temporarily until I can find a better fix.
Is there some other modem that will work with the Mac Mini running High Sierra?
Is there some way to downgrade back to El Capitan?
Maybe some other solution?