It seemed logical for Google to go up a version number from 7.0 to 8.0 with Android O, but the company also went a different route in the past with Android 4.4 KitKat. Since Android O developer preview is now officially out, it is now confirmed that Android O’s version is indeed 8.0.
As for the official name, we still don’t know what the “O” is supposed to represent. Many users thinks it is Oreo, but Google still hasn’t decided.
Regarding the official Android O release date, the platform is expected to be released for Google Pixel phones sometime in August.