Android version history
The version history of the Android mobile operating system began with the release of the Android alpha in November 5, 2007. The first commercial version, Android 1.0, was released in September 2008. Android is continually developed by Google and the Open Handset Alliance, and it has seen a number of updates to its base operating system since the initial release. Versions 1.0 and 1.1 were not released under specific code names. Android code names are confectionery-themed and have been in alphabetical order since 2009's Android 1.5 Cupcake, with the most recent major version being Android 7.0 Nougat, released in August 2016.
Android 1.5 Cupcake
Android 1.6 Donut
Android 2.0 - 2.1 Éclair
Android 2.2 - 2.2.3 Froyo
Android 2.3 - 2.3.7 Gingerbread
Android 3.0 - 3.2.6 Honeycomb
Android 4.0 - 4.0.4 Ice Cream Sandwich
Android 4.1 - 4.3.1 Jelly Bean
Android 4.4 - 4.4.4 KitKat
Android 5.0 - 5.1.1 Lollipop
Android 6.0 - 6.0.1 Marshmallow
Android 7.0 - 7.1.2 Nougat
Note: To clarify, support for e.g. Android 4.4.4 KitKat (Google's support cut-off), means at least security patches in 2014, 2016 and 2017. The updates may or may not reach actual user's devices; that depends on vendors. Google (and others) may support their own users' devices with a major upgrade only, instead of a security update to those older versions, but it's possible to do.
A version of Android KitKat exclusive to Android Wear devices was released on June 25, 2014, with an API level of 20.
Pre-commercial release versions
The development of Android started in 2003 by Android, Inc., which was purchased by Google in 2005.
Alpha There were at least two internal releases of the software inside Google and the OHA before the beta version was released. The code names "Astro Boy" and "Bender" were used internally for some pre-1.0 milestones. Dan Morrill created some of the first mascot logos, but the current Android logo was designed by Irina Blok. The project manager, Ryan Gibson, conceived the confectionery-themed naming scheme that has been used for the majority of the public releases, starting with Android 1.5 Cupcake.
Beta The beta was released on November 5, 2007, while the software development kit (SDK) was released on November 12, 2007. The November 5 date is popularly celebrated as Android's "birthday". Public beta versions of the SDK were released in the following order: November 12, 2007: m3-rc20a (milestone 3, release code 20a)
November 16, 2007: m3-rc22a (milestone 3, release code 22a)
December 14, 2007: m3-rc37a (milestone 3, release code 37a)
February 13, 2008: m5-rc14 (milestone 5, release code 14)
March 3, 2008: m5-rc15 (milestone 5, release code 15)
August 18, 2008: 0.9 Beta
September 23, 2008: 1.0-r1
The main hardware platform for Android is the ARM architecture (ARMv7 and ARMv8-A architectures; formerly also ARMv5), with x86 and MIPS architectures also officially supported in later versions of Android. Unofficial Android-x86 project used to provide support for the x86 and MIPS architectures ahead of the official support. Since 2012, Android devices with Intel processors began to appear, including phones and tablets. While gaining support for 64-bit platforms, Android was first made to run on 64-bit x86 and then on ARM64. Since Android 5.0 Lollipop, 64-bit variants of all platforms are supported in addition to the 32-bit variants. Requirements for the minimum amount of RAM for devices running Android 5.1 range from 512 MB of RAM for normal-density screens, to about 1.8 GB for high-density screens. The recommendation for Android 4.4 is to have at least 512 MB of RAM, while for "low RAM" devices 340 MB is the required minimum amount that does not include memory dedicated to various hardware components such as the baseband processor. Android 4.4 requires a 32-bit ARMv7, MIPS or x86 architecture processor (latter two through unofficial ports), together with an OpenGL ES 2.0 compatible graphics processing unit (GPU). Android supports OpenGL ES 1.1, 2.0, 3.0, 3.2 and as of latest major version Vulkan. Some applications may explicitly require a certain version of the OpenGL ES, and suitable GPU hardware is required to run such applications. Android used to require an autofocus camera, which was relaxed to a fixed-focus camera if present at all, since the camera was dropped as a requirement entirely (except for smartphones) when Android started to be used on set-top boxes.