Bloomberg, Reuters and the Wall Street Journal all think the next iPhone will have a 4-inch screen. Now, 9to5mac is reporting that sources at Apple HQ have been testing phones with a 16:9 display, provided by a 1136 x 640 resolution screen.
The current iPhone uses the 640 x 960 Retina Display, conforming to the standards of previous models which have all featured a display measuring 3.5 on the diagonal, equivalent to a 3:2 aspect ratio. This new 1136 x 640 screen size is rumored to be the same width as the current screen, but taller at 3.45 inches. That makes it pretty much exactly a 16:9 aspect ratio. That seems to make sense: the iPad, for instance, already plays video at 16:9, so it would make sense for this move to occur if Apple wanted videos to play at a native aspect ratio.
The rumored changes in screen dimension have been confirmed to 9to5mac by "undisclosed" employees, who are testing candidate iPhones in "locked shells in order to disguise the exterior design". If such a screen appears on the iPhone, you can expect the home screen to feature an extra row of icons—with no drop in quality thanks to extra pixels along the vertical—and for apps to be redesigned to use the new display real estate.
9to5mac also suggests that the new phone will feature a smaller dock connector, a rumor which has been floating around for some time. In fact, it reports that it is "basically a much narrower version of the current... dock connector" and "between the size of a Micro-USB and Mini-USB connector" in size.
9to5Mac's report mentions "a few next-generation iPhone candidates in testing," including two that feature the 16:9 aspect ratio. But it's not clear if and how those two differ from each other, or what screen size the untold rest of the designs being considered employ. There's also the fact that Apple—and any other company with a half-decent R&D budget—tests multiple versions of every product before final release. Whether these elongated screens are fact or a Jony Ive flight of whimsy remains to be seen.
So, there are some big, big ifs here—but it's certainly looking like a bigger screen is a very, very strong possibility. [9to5mac]