Reports from South Korea suggest that Apple has ruled out a 5.2-inch OLED phone in 2018, and is examining two sizes of OLED screens with one very similar to the iPhone X, plus a large-format LED model.
Reported by The Investor on Monday, citing "local parts makers," Apple has suspended development of a smaller 5.28-inch OLED iPhone. Possiblilities for the 2018 model year include a slightly larger 5.85-inch and 6.46-inch model, with the possible insertion of a greater than six-inch LCD model in the line somewhere.
As a result of the shift, parts manufacturers are reportedly seeing changes in order volumes for future iPhones. Apple has reportedly signed several contracts with Samsung for multiple OLED screen sizes.
At present, the iPhone 8 boasts a 4.7-inch screen. The iPhone 8 Plus is 5.5 inches. The OLED iPhone X has a 5.8-inch screen.
Samsung's Galaxy S8 comes in 5.8- and 6.2-inch sizes.