Google released the first developer version of the Android P, which will be the successor of Android 8 Oreo. However, less than 1.5% of Android phones run on Android 8 Oreo right now. To improve this, Google introduced Project Treble which enables the faster Android updates, without interfering with the OEM.
Google follows the 2 years update policy, where the smartphones and tablets will receive two major OS upgrades. However, this changed with the launch of the Pixel series of smartphones. To keep up with Apple (which offers four major OS upgrades), the Pixel devices will receive three major OS upgrades. Similarly, the Pixel will update to Android P and Android Q and the Pixel 2 will also be updated to Android R.
However, this is not applicable to the Pixel C tablet, Nexus 5X and the Nexus 6P. These devices have received two major software update and they are no more eligible to receive Android P. However, all three devices are eligible to receive monthly security updates until September 2018.
As these devices are very popular amongst the developers, the devices might receive unofficial build of Android P via third-party developers. 
Android P Features
The Android P is expected to overhaul the user interface completely. In fact, the biggest change is the native support for the infamous notch. In fact, one can test these features by installing the developer version on a supported device.
The dock in Android P will also look like a dock now. The four app icons along with the Google Search bar will have a cloudy background, distinguishing it from the rest of the screen. A microphone icon has been added to the Google Search bar to access Google Assistant or do a quick voice search. The volume slider has been moved to the side of the screen and shrunk in size.
Another feature added is something that has been there in custom skins for a while. A user can now take a screen from the power menu, that pops up by long pressing the lock/unlock button. This will come in handy during one handed usage. Visually, there are not many changes in the first developer preview of Android P. However, this can change by the time the official version rolls out. Google might introduce a few visual changes or keep it the way it is. Time will tell.
