Apple announced some time ago that radical changes in the appearance of the iPhone can be expected every 3 years. This period was coming to an end, as indicated by the rumors that have appeared in many sources.
In September, the company plans to present new versions of the iPhone 7s and iPhone 7s Plus, but that's not all - probably iPhone 8 also will see the light of day. iPhone 8 will look different than iPhone 7s or 7s Plus - as reported by several websites, this phone will have a curved display on each side, and in addition this display will be made in OLED technology. Under the display Apple plans to include fingerprint readers.
When it comes to the iPhone 7s and 7s Plus, it is likely they will have LCD screens, not OLED.