I want notifications to be displayed on the lock screen. I know it may be done on android 5.0 and newer (set visibility to public), but is there any way to do the same on older phones, like Facebook app does? I've heard one way doing this is to create some lick screen widget, but I am new to mobile programming and don't even now what widget is. So, is there any other, easier way to display notifications on old phones? At least , is there any tutorial about how those widgets may be created and does Xamarin support it?