Apple may seek to placate this market by updating its 4-inch line-up. And while they have been consistently outsold by the iPhone 6 and 6s, the Plus models haven't been a sales disaster either - and they're important products for Apple in terms of prestige and acquiring a foothold in new markets.
For simplicity, therefore, we're predicting three new iPhones from Apple over the next year or so. An update of the iPhone 5s with a 4-inch screen, which could be called the iPhone 7 mini; a 4.7-inch update of the iPhone 6, which we're calling the iPhone 7; and a new phablet, based on the iPhone 6 Plus, with a 5.5-inch screen. This last update is the one we're calling the iPhone 7 Plus.
Does the new iPod touch make an updated 4-inch iPhone more likely?
Our colleague Jason Snell, writing for Macworld US, discusses the theory that Apple's recent refresh of its iPod touch line may signal a similar update to its line of 4-inch iPhones.
"The new iPod touch, for all its advancements, still sports the same 4-inch Retina display as the iPhone 5, 5s, and 5c. And it makes me wonder if maybe, just maybe, it's the first hint that we'll be seeing an updated 4-inch iPhone this fall.
"My guess is that there will be a new 4-inch iPhone this fall. It might look more like a small iPhone 6, or it might take a cue from the new iPod touch and remain exactly the same on the outside, while being completely different internally. But will it be a "cheap iPhone"? I doubt it. More likely, it'll be outfitted with last year's iPhone 6 technology and fill the slot that's one step down from whatever replaces the iPhone 6."
There are plenty of fans of the smaller, 4-inch-screen form factor here in the Macworld UK office, and we think it would be unwise of Apple to abandon this market entirely.
iPhone 7 specs rumours: 3D display
The iPhone 7 could feature a 3D display, according to Economic Daily News, which claims that Apple supply chain partner TPK is working on a project that relates to "naked eye 3D screen" - in other words, a 3D screen that doesn't require glasses to see.
iPhone 7 specs rumours: OLED display
We leave this until last, because it's a rumour that apparently affects the iPhone 8 generation rather than the upcoming iPhone 7.
Samsung, which supplies components for the iPhone range despite being a major rival in the smartphone market, has reportedly been pressuring Apple into using OLED screens rather than the LCD ones currently included.
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