*Android 1.0
*Android 1.1
-On February 9, 2009, update was released, initially for the HTC Dream only. Android 1.1 was known as "Petit Four" internally, though this name was not used officially. The updateresolved bugs.
*Android 1.5 CUPCAKE
-On 27 April 2009, the Android 1.5 update was released, based onLinux kernel2.6.27. This was the first release to officially use a codename based on a dessert item ("Cupcake"), a theme which would be used for all releases henceforth. The update included several new features and UI amendments.
*Android 1.6 DONUT
-On 15 September 2009, the Android 1.6 SDK – dubbed Donut –was released, based on Linux kernel 2.6.29. Included in the update were numerous new features.
*Android 2.0 ECLAIR
-On 26 October 2009, the Android 2.0 SDK – codenamed Eclair – was released, based on Linux kernel 2.6.29. Changes included.
*Android 2.2–2.2.3 FROYO
-On 20 May 2010, the SDK for Android 2.2 (Froyo, short forfrozen yogurt) was released, based on Linux kernel 2.6.32.
*Android 2.3–2.3.7 GINGERBREAD
-On 6 December 2010, the Android2.3 (Gingerbread) SDK was released, based on Linux kernel 2.6.35.
*Android 3.0-3.2 HONEYCOMB
-On 22 February 2011, the Android 3.0 (Honeycomb) SDK – the first tablet-only Android update – was released, based on Linux kernel 2.6.36. The first device featuring this version, the Motorola Xoomtablet, was released on 24 February 2011.
*Android 4.0–4.0.4 ICE CREAM SANDWICH
-The SDK for Android 4.0.1 (Ice Cream Sandwich), based on Linux kernel 3.0.1, was publicly released on 19 October 2011. Google's Gabe Cohen stated that Android 4.0 was "theoretically compatible" with any Android 2.3.x device in production at that time.The source code for Android 4.0 became available on 14 November 2011. Ice Cream Sandwich was the last version to officially supportAdobe Systems'Flash player.
*Android 4.1 JELLY BEAN
-Google announced Android 4.1 (Jelly Bean) at the Google I/O conference on 27 June 2012. Based on Linux kernel 3.0.31, JellyBean was an incremental update with the primary aim of improvingthe functionality and performance of the user interface. The performance improvement involved "Project Butter", which uses touch anticipation,triple buffering, extended vsynctiming and a fixed frame rate of 60fps to create a fluid and "buttery-smooth" UI. Android 4.1 Jelly Bean was released to the Android Open Source Projecton 9 July 2012, and the Nexus 7" tablet, the first device to run Jelly Bean, was released on 13 July 2012.
*Android 4.4 KITKAT
Google announced Android 4.4 KitKat, internally known as Project Svelte, on 3 September 2013. The release had long been expected to be numbered 5.0 and called 'Key Lime Pie'. KitKat debuted on Google's Nexus 5, and has been optimised to run on a greater range of devices, having 512 MB of RAM as a recommended minimum.
credit: rave