Following the launch of LG's pOLED displays, we had many recent discussions and reports of OLED burn-in and Image-Retention. Apple now released a support document for the iPhone X, its first OLED phones, in which it warns users that “image persistence” or “burn-in” is an "expected behavior".
Apple says it engineered the display to be the best in the industry in reducing the effect of OLED burn-in, though. Apple also says that its OLED could have noticeable but slight shifts in color and hue when seen off-angle. The iPhone X has a 5.8" 1125x2436 Samsung-made Super AMOLED display.
Here's Apple complete message: If you look at an OLED display off-angle, you might notice slight shifts in color and hue. This is a characteristic of OLED and is normal behavior. With extended long-term use, OLED displays can also show slight visual changes. This is also expected behavior and can include “image persistence” or “burn-in,” where the display shows a faint remnant of an image even after a new image appears on the screen. This can occur in more extreme cases such as when the same high contrast image is continuously displayed for prolonged periods of time. We’ve engineered the Super Retina display to be the best in the industry in reducing the effects of OLED "burn-in."