There are many reports that detail Apple's 2017 iPhone lineup, and it seems quite certain that Apple will indeed release a high-end iPhone model that will adopt a flexible OLED. Those OLEDs will be produced by Samsung Display (Apple apparently paid $4 billion in advance to secure those displays).
According to a new report from Fast Company, Apple will introduce three new iPhones in 2017 - the iPhone 7S and 7S Plus, with 4.7" and 5.5" LCD displays, and premium 5.8" iPhone that will sport the OLED display. Fast Company says that this phone will be called the iPhone X (as in the 10th iPhone), and it introduce several new features (besides the new display technology) - and carry a price tag of over $1,000.
This sounds like a lot, but actually Apple's current iPhone 7 Plus 256GB costs $969, so this is not so outrageous. Still this will limit the appeal of the new OLED model.