In this year’s Google I/O Conference, it was announced that there will be a new version of Android OS which goes by the name of Android M. Now, the Android M developer preview is available to download from here.
Since it is the developer version, it is not the final product which is going to be released to the public and expect a lot of new features which is promised during the conference is not fully developed or there is a lot of bugs on it or the features are not even implemented into the OS yet. Therefore, even after all these warnings, you still want to install this version into your Android device, it is recommended that you backup your current content first before doing anything else. It is so that if some things happen and you can restore your Android device without any trouble.
There are a few differences between Android 5.0 Lollipop and Android M OS. One of the differences is that in the Lollipop OS, the notification which pops up at the top of the screen cannot be customized according to users’ preferences, but with Android M, users are able to set them on per-app basis, which of course, will make them happy. It makes me happy. There is also an additional new “Tap & Pay” screen which seems to be meant for Android Pay.
Lastly, the developer preview of Android M can be reversed back to Android Lollipop by following the instructions here.