Android 1.5 Cupcake
Android 1.5 Cupcake featured video recording and upload to Youtube, APIs for creating home screen widgets, support for an on-screen soft keyboard and Android virtual devices (AVDs).
Android 1.6 Donut
Android 1.6 Donut bought new user features: Quick search box, new interface for camera and galleries, battery usage indicator and Google Play updates. Text-to-speech engine was introduced along with expanded support for screen densities and resolutions.
Android 2.0/2.1 Eclairs
The new features in Eclairs were multiple accounts that could be added to a device for email and contact synchronization, including Exchange accounts. Search functionality for all saved SMS and MMS messages. Other upgrades included Android virtual keyboard, refreshed UI with actionable browse and calendar updates.
Android 2.2 Froyo
The main feature of Android 2.2 Froyo was the just-in-time compiler which boosted the speed of the applications over three times. Other features include automatic app updates for both application developers and users, FM Radio and OpenGL improvements.
Android 2.3 Gingerbread
Support for Gyroscope, rotation vector, linear acceleration, gravity, and barometer sensors were the major additions in this update for gaming applications. New UI and keyboard interface was introduced. Other features included near-field communications, front-faced camera support, app manager, copy & paste, better audio for apps, and extra large screen support.
Android 3.0 Honeycomb
New UI designed from the ground-up for tablets. System bar for global status and notifications was introduced. Customizable home screens with recent apps, for easy visual multi-tasking interface was introduced. Improved text selection, with copy and paste with new updates for standard phone apps.
Android 4.0 Icecream Sandwich
Icecream Sandwich was the step into the next gen for Android. It had a much refined and evolved UI, Home screen folders and favourites tray, resizable widgets, New lock screen actions, quick responses for incoming calls, Swipe to dismiss notifications, tasks, and browser tabs.
Android 4.1 Jellybean
Gesture mode for blind, transfer over Android beam, and text traversal in accessibility were some of the feature updates in Jellybean. More improvements were in store for browser, calendar, camera and gallery. Faster, smoother, more responsive with refined UI was another feature.
Android 4.4 Kitkat
4.4 was in a league of its own with its Cloud system, lightweight RAM, Pallet colour, remarkable CPU management, good multi cores and screen orientation. It also came in for much praise for reducing battery consumption.