everybody thinks the next iPhone's going to be a huge step. half true, half false. next year Apple will expand the iPhone line, and finally separate iPhones: entry-level, main users (two sizes), and business users. And of course Apple must at least prepare for VR, but more likely release a VR product connected with iPhone. This way needs screen resolution improvement, and there must be a well comunicable change for every iPhone.
iPhone: Retina 2K, 4.7" 2048*1152, 500ppi, with Home button
iPhone Plus: Retina 2K, 5.3" 2304*1296, 500ppi, with Home button
a new individual category for comprehensive business use:
iPhone Pro: curved OLED Retina 4K, 5.8" 4096*2160, 800ppi, with no Home button, new design with no camera bump (but 0.3“ thick), extra features comming annually in the first three models (sapphire glass, IP68, real 4-core A11, 4 GB RAM, USB 3 speed, smart connector, no SIM card, split view, AirPlay Pro for desktop use, fast+wireless charging, all-day usage, stereo sound recording, four speakers, laser focus, 4K slo-mo, Bluetooth 5, 5G etc.), from 899 €
entry-level iPhone stays fancy but not the smartest one: similar construction, improved features (camera, processor, connections), new functions rarely.
in 2018 the Home button and SIM cards leave the iPhones forever and the new design and OLED screen both arrive to all iPhone already (except the entry-level one).