I have a Sony Z1 Compact. Android 5.0 had a beautiful silent mode. Pushing the power button the screen went on, locked, and when you pressed the volume button you could set it to silent, optionally for several hours.
Recently I've upgraded to Android 5.1, and this option has disappeared. The strange thing is that when I google for this, I find that Android 5.0 had no silent mode, and 5.1 has exactly what I want and how it was for 5.0 on my phone.
How can I use silent mode on my Z1C with Lollipop 5.1?