According to iOS developer Steve Troughton-Smith (via Cult of Mac), he has discovered that there are code references made to an iPhone that closely resembles the iPhone 7. The phone in question is codenamed T500 and will feature the A10 processor, the same screen resolution as the iPhone 7, and also the same amount of RAM, and it is also expected to largely retain the design of the iPhone 7 which means that Apple won’t be fully transitioning to the iPhone X’s design just yet.
So as found by @_inside, Xcode 10b6 has references to an unreleased iPhone, the t500, with an A10 CPU and the same screen resolution & RAM of the iPhone 7. Presumably this would take the place of the existing iPhone 7 as the entry model iPhone (replacing the 6s in the lineup)
— Steve Troughton-Smith (@stroughtonsmith) August 22, 2018
What this means is that in addition to the 5.8-inch and 6.5-inch OLED iPhones and the 6.1-inch LCD iPhone, Apple could have another lower-end iPhone to appeal to customers who probably don’t want to fork out as much money for the newer models. Like we said, Apple typically keeps older models around when new models launch.
For example right now Apple’s lineup consists of the iPhone X, 8, and 8 Plus as its existing flagship models, but they also have the iPhone 7 and 6s and SE as part of its lineup which are priced lower than the current flagships.