Based on the current rumors, we could see a radical new design change, 521ppi pixel density, a return of glass back, waterproof, wireless charging, 3D sensors, removal of the home button, running on Apple’s A11 processor with 3GB of RAM, curved screen, dual cameras and bezel-less display.
There's a good possibility that there will be 2 versions of the iPhone 8 and then a premium model that celebrates the 10th anniversary of the iPhone.
From Mashable:
Apple is rumored to be launching three new iPhones this fall: Two with a regular, LCD screen, and a “premium” variant that will have a curved OLED screen. Judging by the size of this order, Apple expects this version — which is also rumored to be pricier than usual — to sell well.