If that resolution were to be applied to the 4.7-inch model, it would effectively give it a higher pixel density than the 5.5-inch model. In fact that resolution applied to the 5.5-inch model would be a bit of a downgrade even when compared to the iPhone 5s. However according to a recent report from John Gruber of Daring Fireball, he has offered up some possible resolutions for the 4.7-inch model and 5.5-inch model.
We should point out that Gruber arrived at these resolutions through some math, as opposed to finding evidence of it online or through a source, but given that Gruber is known for having connections with Apple and has been quick and accurate at debunking rumors, perhaps there could be some truth to his claims.
Gruber uses the Pythagorean Theorem and has calculated that the 4.7-inch model will have a resolution of 1334×750, thus giving it a pixel density of 326ppi and also keeping it in line with Apple’s definition of “Retina” quality. As for the 5.5-inch model, Gruber seems to believe that it could feature an even higher resolution – 2208×1242, giving it a pixel density of 461ppi.
According to Gruber, he believes that with these resolutions, it will allow Apple to easily upscale the pixels of existing apps, thus allowing non-Retina apps to continue to work fine on the newer iPhones and displays. Of course this is just speculation for now so take it with a grain of salt, but hopefully we will find out more come 9th of September which is when Apple is rumored to announce the new devices.