In the past, when Apple has grown the screen of an iOS device — for example, with the transition from the iPhone 4s to the iPhone 5 — Apple has taken pains to keep the pixel density the same. The Retina Display on the iPhone 5 is 326 pixels per inch, just like the iPhone 4s. This makes it easier for developers and helps prevent the widespread fragmentation seen in the Android operating system.
With many rumors pegging the forthcoming iPhone 6 as having a much bigger 4.7-inch display, a practical issue presents itself: what would that mean for resolution and pixel-density? If Apple increases the display size, will they increase the resolution to compete with the likes of HTC and Samsung’s 1080p Android smartphones? And if so, what does that mean for app developers?