Latest industry rumors suggest that Apple might finally do away with LCD displays for iPhones by 2018. It will greatly improve the already excellent battery life of the iPhones, and offer better contrast and deeper blacks.
Currently, all Apple products use LCD displays with the exception of Apple Watch, which relies on OLED display. Apparently, some suppliers have already been notified about the move. The high demand for iPhones all over the world has led to reports hinting that Apple might introduce two variants, one with OLED displays, and the other with LCD displays. On the other hand, LG has already started working on its displays and capacity upgrades.
Currently, Samsung is the only other major phone manufacturing company offering OLED displays, with a demand that comes close to Apple iPhones. The move might also lead to a heavy blow to Japan Display, and Sharp, the two companies that currently supply LCD displays to Apple. Reports indicate that Apple displays make up for over a fourth of the sales made by Japan Display. However, Apple is already said to be negotiating with the suppliers to minimize the shortcomings of OLED panels so that they last longer.
As for redesigning the look of the phone, Apple might choose to go for black backgrounds with bright icons, similar to Apple Watch. Although the company has been avoiding the use of the same technology for iPads and iPhones (citing problems of over-saturation), it looks like it is finally evaluating its options and moving to OLED panels.