Apple is testing an iPhone 6 with a 1704 x 960 resolution screen, 9to5Mac reports. The new resolution will be achieved by tripling the initial iPhone “base resolution” of 568 x 320. On a 4.7” screen, the pixel density would be 416 PPI; on a 5.5” screen, the density would be roughly 356 PPI. The aspect ratio will remain 16:9 — though not quite full 16:9 HD, which would be at 1920×1080 resolution, and would allow for 1:1 pixel sharing between an iPhone and an HDTV.
Though it’s expected that most UI elements of iOS will simply appear larger than before on the new screen, it’s possible the home screen and other functions could be redesigned in some way to better utilize the screen space. It should be easy for developers to make the transition to the new resolution due to a reduced reliance on raster graphics in iOS 7 — Apple is also working on a “multi-resolution” mode and developer toolset that will make it easier to scale applications to fit on multiple iOS devices with different resolutions.