Apple's move to adopt OLED displays in its future iPhone devices has been reported so many times, that analysts assume that this is highly likely to happen in 2017 or 2018. It seems that now they are starting to look further down the road, and respected Apple analyst Ming-Chi Kuo from KGI expects Apple to adopt flexible AMOLED Panels in its 2018 iPads.
Back in 2015 it was reported that Apple wants to use OLEDs in future iPads - and that the company contracted JOLED to produce those OLEDs. That 2015 report was probably groundless, but it seems plausible that if Apple moves to flexible OLEDs, it will eventually want to adopt these displays across its entire mobile product line. Whether there's anything behind this latest estimation from KGI, I do not know.