Android has evolved through several versions since its initial release in 2008. The first commercial version was 1.0 Angel Cake in 2008. Subsequent major versions included 1.5 Cupcake, 1.6 Donut, 2.0 Eclair, 2.1 Froyo, 2.3 Gingerbread, 3.0 Honeycomb, 4.0 Ice Cream Sandwich, 4.1 Jelly Bean, 4.4 KitKat, 5.0 Lollipop, 6.0 Marshmallow, and 7.0 Nougat, with each release adding new features and functionality to the mobile operating system. The document traces the history and key developments of the Android OS through its various versions.