How to disable Heads Up notifications in Android Lollipop? (notification popup at top of the screen) How can I disable the heads up for Android Lollipop, just like it was in KitKat and below?  

If it is possible to disable heads up, is it also possible to enable it for certain apps only , like when I receive a call?
A non root option is now available. The HeadsOff app can disable all Lollipop Heads-up notifications on your phone. It can also disable Heads-up notifications only for selected apps. If you purchase the Pro key you can restore the ticker text in the status-bar to see a little notification preview.