Android : How to set ringing mode to silent in Lollipop

Prior Lollipop i was using below code to Mute Ringing Tone

// Mute Ringtone

AudioManager amanager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
amanager.setRingerMode(AudioManager.RINGER_MODE_SILENT);

It is not working anyomore on devices runnning on lollipop. It although sets the priority mode but do not silence at all. Any help will be appreciated.