I know that this has been discussed on other threads, and I know that Sonos’ position is that the controller app does not support hardware volume control on iOS. And as a recent convert from Android to iPhone I was disappointed to find that I had to unlock my phone and go to the app every time I want to control the volume. However, on a recent trip to visit my brother, I was complaining about this, and he says, “it works fine for me.” Lo and behold, I tried it on my phone and was able to control the volume on his S1 system. When I contacted Sonos about this, there only answe was “we don’t support hardware controls on iOS.” Hmmmmm.