This is the most famous Android 4.4 also known as KitKat, after the famous chocolate treat. It was announced a few months ago and just released on 1 Nov, together with the much leaked Nexus 5 from LG.
There a whole bunch of write up how Android 4.4 will reduce memory consumption, faster through a new JVM called ART, all to enable leaner hardware to run the latest version of Android. Leaner, not older hardware.
Personally, I would like try out printing supported right from the Android, immersive viewing and full screen wallpaper. What I am not so keen on are the changes in the colors in the UI. From the light blue-green, it is going grey. Grey on a color device? Very funny!
Those holding on to much older devices will have to wait for a dev to watch the patches to AOSP and finally, build one.