El Capitan

Good afternoon, in an vacation house I have a two keyboard console and an older Mac with OS El Capitan, the HW key I have at home I use it with a Mac with Mojave I suppose with the correct update, the question is connecting the HW key to a Mac with El Capitan will work, thank you

Yes it should. I used Hauptwerk with El Capitan for some time. I would recommend to use the driver downloadable from the Hauptwerk website.