There is also a much easier way of getting the “Classic” UI without SSHing into Volumio.
Select the top left burger menu, then select system.
Scroll down to “Legacy UI interfaces”. By default it is on “manifest”
Do not select anything from the drop down box … just click “Save”.
Scroll down again to “Legacy UI interfaces” and this time select “Classic” from the drop down menu and click “Save” which should now work as normal giving you the Classic UI
But…If you want to change the background in Classic you still have to edit a file to achieve this