In mobile operating system category android completed 10 years in the market. In 23 September 2008 android operating system lunched first phone in the international market. There is no code on that android system. That is called android 1.0 operating system.
There after google lunched android petite 4 version. After that they lunched cupcake, Donut, eclair, Froyo, gingerbread, honeycomb, ice cream sandwich, jellybean, kitkat, lollipop, marshmallow, nougat, oreo, Now present running version is rinav (9.0) version.