Although Android 5 is eagerly awaited, Google has released an update to the current version. While Android 4.3 is only a minor upgrade it caters for Nexus 7 tablets that are expected to ship shortly and adds features that make current Jelly Bean devices more functional.

For developers the most important upgrade is the use of Open GL 3.0 ES, the latest industry standard for accelerated 3D graphics which permits incorporating photorealistic images in games. According to the Android blog:

blades of grass on the soccer field come alive, asphalt on the street looks real as you screech by, stubble on a villains' face almost pokes out of the screen. And with sophisticated effects like self-shadows, that villain looks even more menacing, casting a shadow on himself.

Well this might be a bit poetic rather than technical but you get the general idea - OpenGL 3.0 ES is better because it offers more subtle rendering. 

The new hardware announced at the same event - the new Nexus 7  provide a suitable platform for running the new graphics. The new Nexus 7 has a 1920×1200 resolution compared to the older 1280×720 resolution. It also has upgraded CPU and GPU to make things faster. 

Another advance is in restricted profiles, which can be used to manage per-user access to apps and content. For example, it enables parental controls, to govern access mature content or vendors could use tablets as kiosks that show product information or as point of sale systems, while limiting access to apps. You can find out more in the following video:

Bluetooth Smart is an energy saving feature also referred to as Bluetooth Low Energy (BLE). It minimizes power usage while measuring and transmitting data, making both sensors and the phones or tablets connected to them more battery-efficient. This feature also means that devices like Nexus 4 and Nexus 7 (2013 edition) will be able to connect to sensors that provide information about fitness, proximity, medical monitoring and more. Android 4.3 also has Bluetooth AVRCP 1.3 support , allowing it to display song titles on a car stereo.

You can find out more about the new BLE API in the following video: 

It seems that the original Nexus 7 doesn't support BLE but the new version and Nexus 4 do. 

Also new is a DRM Framework which will allow programmers to integrate their own DRM within streaming protocols. It is a similar to the recent HTML DRM system in that it allows plugins to mange custom DRM.  It is difficult to work out how important this is but NetFlix has already announced 1080p streaming for Android 4.3 users.  You also now have access to a VP8 encoder. 

Another new feature is the ability to interact with notifications - you can basically intercept the stream of status bar notifications. Yes it seems to be a full read/write/delete API. While I can think of one or two applications for this I'm not convinced that it's going to be a big thing. 

On a more prosaic note there's a new autocomplete feature in the dial pad that will suggest phone numbers or names as soon as the user start touching numbers or letters. Whether this is a timesaver or frustrating depends on how you like to interact with your Android device - but it is an optional feature that has to be turned on to work.

Android 4.3 introduces further localization features by way of additional language support - Android is now translated into Africaans, Amharic, Hindi, Swahili and Zulu - and right-to-left text layour support for languages such as Hebrew and Arabic in the home screen, settings, and Phone, People, and Keep apps.

There are a few other minor UI and API improvements and some improved profiling tools, including GPU profiling. 

The new Android 4.3 platform is immediately supported by Android Studio and in Eclipse. Simply use the SDK Manager to download the new SDK:

The Android Support Library has also been updated to allow you to use features with earlier versions of Android. Most important is support for the Action Bar API which allows you to use this UI design all the way back to Android 2.1. If you want to make use of the new Open GL ES 3.0 APIs you will also need to download Android NDK (r9). 

One final thought: would this announcement have made this year's Google IO seem more exciting?