Countless reports claim that the 2017 iPhone 8 (or will it be a >$1000 iPhone X?) will use AMOLED displays for at least one variant. Most of these reports suggested that Apple want to use a flexible curved AMOLED display.
TrendForce, following talks to supply chain sources, now says that Apple was not happy with the production yields and drop-test results of those flexible OLEDs, and the company decided to adopt a flat display (with rounded edges, what is called 2.5D glass). This design is similar to the one used in current iPhone models.
TrendForce estimates Apple will still use an AMOLED display, but a rigid one. If Apple did indeed decide not to use a flexible OLED, it may be that the company will not use an OLED display at all but rather an LCD for all of the 2017 iPhone models.
This has interesting repercussions - reports from 2016 suggested that Apple paid $4.3 billion upfront to secure 100 million panels, and a few days ago it was reported that Apple ordered an extra 60 million OLED panels from Samsung Display. It may be that Apple decided to delay its OLED adoption to 2018...