As you can see the layout is starting to look quite cramped. When new devices are released int he Autumn we are going to seriously consider a complete redesign.
Version 2.4 adds iOS 7, updated stats (we now use Apple's official published stats) and reassessed support colouring.
In summery you should't supporting anything < iOS 5.0 and in practice only support Retina class devices and iOS 6 (+ iPad Mini).
Clicking on the image above will download a vector PDF that you can print at high quality.