I have avast home running on one pc with simple user interface after an update a few months ago. My other two pc’s do not have the simple user interface after multiple updates over the last few months. They both still have that ugly GUI that looks like it’s from my old car.
Or if you are looking to do away with the radio look, go to the upper left of the radio, click on the menu arrow, → settings → common → uncheck enable skins for simple user interface. Close it out and then reopen and the radio is now gone and replaced with the normal simple user interface.