Intro of Android ~ from android 1.0 until android 3.X..

1.0	Released 23 September 2008[37]
1.1	On 9 February 2009, Android 1.1 update for Android was released for T-Mobile G1 Only. Included in the update were:[38] Multiple resolved issues API changes Maps adds details and reviews Screen timeout longer when using speakerphone "Show" & "Hide" Dialpad included in-call menu Support for saving attachments from MMS Support for marquee in layouts
1.5 (Cupcake) Based on Linux Kernel 2.6.27	On 30 April 2009, the official 1.5 (Cupcake) update for Android was released.[39][40] There were several new features and UI updates included in the 1.5 update:[41] Ability to record and watch videos through camcorder mode Uploading videos to YouTube and pictures to Picasa directly from the phone A new soft-keyboard with text-prediction Bluetooth A2DP and AVRCP support Ability to automatically connect to a Bluetooth headset within a certain distance New widgets and folders that can populate the Home screens Animated screen transitions
1.6 (Donut) Based on Linux Kernel 2.6.29[42]	On 15 September 2009, the 1.6 (Donut) SDK was released.[43][44] Included in the update were:[42] An improved Android Market experience An integrated camera, camcorder, and gallery interface Gallery now enables users to select multiple photos for deletion Updated Voice Search, with faster response and deeper integration with native applications, including the ability to dial contacts Updated search experience to allow searching bookmarks, history, contacts, and the web from the home screen Updated technology support for CDMA/EVDO, 802.1x, VPNs, and a text-to-speech engine Support for WVGA screen resolutions Speed improvements in searching and camera applications Gesture framework and GestureBuilder development tool Google free turn-by-turn navigation
2.0 / 2.1 (Eclair) Based on Linux Kernel 2.6.29[45]	On 26 October 2009, the 2.0 (Eclair) SDK was released.[46] Changes include:[47] Optimized hardware speed Support for more screen sizes and resolutions Revamped UI New Browser UI and HTML5 support New contact lists Better contrast ratio for backgrounds Improved Google Maps 3.1.2 Microsoft Exchange Server by Exchange ActiveSync 2.5 support Built in flash support for Camera Digital Zoom MotionEvent class enhanced to track multi-touch events[48] Improved virtual keyboard Bluetooth 2.1 Live Wallpapers The 2.0.1 SDK was released on 3 December 2009.[49] The 2.1 SDK was released on 12 January 2010.[50]
2.2 (Froyo)[51] Based on Linux Kernel 2.6.32 [52](2.2.2 latest release)	On 20 May 2010, the 2.2 (Froyo) SDK was released.[51] Changes included:[52] General Android OS speed, memory, and performance optimizations[53] Additional application speed improvements courtesy of JIT implementation[54] Integration of Chrome's V8 JavaScript engine into the Browser application Increased Microsoft Exchange support (security policies, auto-discovery, GAL look-up, calendar synchronization, remote wipe) Improved application launcher with shortcuts to Phone and Browser applications USB tethering and Wi-Fi hotspot functionality Added an option to disable data access over mobile network Updated Market application with batch and automatic update features[53] Quick switching between multiple keyboard languages and their dictionaries Voice dialing and contact sharing over Bluetooth Support for numeric and alphanumeric passwords Support for file upload fields in the Browser application[55] Support for installing applications to the expandable memory Adobe Flash 10.1 support[56] Support for extra high DPI screens (320 dpi), such as 4" 720p[57]
2.3 (Gingerbread)[58] Based on Linux Kernel 2.6.35[59]	On 6 December 2010, the 2.3 (Gingerbread) SDK was released.[58] Changes included:[59] Updated user interface design Support for extra-large screen sizes and resolutions (WXGA and higher)[57] Native support for SIP VoIP telephony Support for WebM/VP8 video playback, and AAC audio encoding New audio effects such as reverb, equalization, headphone virtualization, and bass boost Support for Near Field Communication System-wide copy–paste functionalities Redesigned multi-touch software keyboard Enhanced support for native code development Audio, graphical, and input enhancements for game developers Concurrent garbage collection for increased performance Native support for more sensors (such as gyroscopes and barometers) A download manager for long-running downloads Improved power management and application control Native support for multiple cameras Switched from YAFFS to the ext4 filesystem[60]
3.0 (Honeycomb)[61]	On 26 January 2011, a preview of the 3.0 (Honeycomb) SDK was released. Changes include:[62] Optimized tablet support with a new user interface Three dimensional desktop with redesigned widgets Refined multi-tasking Browser enhancements including tabbed web pages, form auto-fill, bookmark syncing with Google Chrome, and private browsing Support for video chat using Google Talk Hardware acceleration Support for multi-core processors
Ice Cream Sandwich[63]	Possible mid-2011 release.[63]