I may assume that Multiroom feature to be major milestone introduced in Volumio3.
But my system, as might be for most users, only complies of a Single Device. But then, when opening Volumio through Android App… it always pop-up the user to select a Device, even so… if there is “only 1” (that is… an annoyance and/or distress).
Suggestion is that if not more than one Device detected, or originally selected, that the Device pop-up on App does not show. Or… another option, a turn-on/off switch for the user to address the use of Multiroom… or not.
Xant