Apple is looking to introduce two large-screened iPhones in September, according to an increasing number of leaks from the company's Chinese supply chain.
The smaller of the two would have a display measuring 4.7in diagonally compared with 4in for the current iPhone 5S. That would be around the same size, but not necessarily aspect ratio, as Amazon's recently released Fire Phone, or the 2012's Samsung Galaxy S III.
The larger of the rumoured phones would be 5.5in, firmly in "phablet" territory, equivalent in size to Samsung's 5.7in Galaxy Note 3.
According to Bloomberg, which reported the latest round of leaks, the new iPhones "will also be rounder and thinner than previous models." The site also reported that the larger model is facing production hurdles due to its complexity, "resulting in lower production efficiency that must be overcome before manufacturing volume can be increased."
As for what that complexity entails, a research note from analyst firm KGI suggests one possibility: that the 5.5in model will ship with a camera lens outfitted for optical image stabilisation. "The 5.5in iPhone 6 is more likely to be equipped with [optical image stabilisation] due to lower estimated shipments and the need for more product features to differentiate itself from the 4.7in iPhone 6," the analysts say.
Bloomberg's report is by no means the first to suggest that the latest iPhone will be larger than the 5s, nor even the first to finger 4.7 inches as the specific display size. In February, reports from Taiwan's Economic Daily News made broadly the same claims as, describing 4.7 and 5.6 inch models as being in production
And the smokiest gun of all came at Apple's WWDC event, where the firm detailed the new technology that will be going in to iOS 8, likely to debut alongside the new iPhones. A feature called "adaptive display" lets developers program assets for screens of unknown or varying sizes – exactly what would be needed if the iPhone lineup was to fragment into small, medium and large models.
That feature is just the latest in a line of additions that make iOS more suitable to large screens; the swipe functionality introduced in iOS 7 allows one-handed use of larger devices by rendering the awkwardly-placed back button -placed at the top left of the screen on older software and so furthest from the thumb - unnecessary.
As well as size, another consistent thread has emerged: that the glass used in the screens of the new iPhones will have some fancy properties of its own. Apple has begun to buy sapphire crystal, the ultra-hard material which it currently uses only in the lenses of its cameras, in larger quantities than ever before, while reports from Bloomberg in November as well as patents filed in January suggest that pressure sensitivity may be in the pipeline, letting the devices distinguish between heavy and light touches. However, that feature may not make it in to the latest devices.
As Apple's hardware chain grows, leaks like this look likely to become more and more common. Back in 2009, barely anything was known about the iPhone 3G before it made its debut, but in the entire first quarter, just 6.9m units were sold. Four years later, the iPhone 5S sold more than 50m units, and largely avoided supply chain shortages throughout (with the exception of the coveted gold model).
But Apple could only pull that off by involving an order of magnitude more people in the process before launch. And as scale grows, secrecy shrinks. However that does not seem to hold for software: Apple announced Swift, a whole new programming language, to a completely unsuspecting audience at WWDC.
For the first five years of its life, the iPhone came in just one screen size, the same 3.5in model that the original model was available in. The iPhone 5, released in September 2012, was the first with a larger screen, measuring 4in, but even at the time of its release, it was still significantly smaller than top-end Android phones. The contemporaneous Samsung Galaxy SIII had a 4.8in display.
But Apple has never said conclusively that it wouldn't bring out a phone that was larger still. When asked about the possibility in February this year, Tim Cook said that "until the technology is ready, we don’t want to cross that line. That doesn’t say we’ll never do it. We want to give our customers what’s right in all respects – not just the size but in the resolution, in the clarity, in the contrast, in the reliability. There are many different parameters to measure a display and we care about all those, because we know that’s the window to the software."
One other reason is likely the firm's passion for consistency, says Roberta Cozza of analyst firm Gartner. Tim Cook is famously proud of the fact that all of Apple's products can fit on one table, in contrast to the likes of Samsung, who have hundreds of models of phone available at any one time.
"I think that Apple has been happy to have a more consistent portfolio to help the ecosystem of developers," says Cozza. "But at the same time, to give Samsung credit, it has been the vendor that has the scale and can afford to be more experimental. They found this niche of bigger display phones, that is very attractive for Asian markets."
Cozza argues that the reason for the steady upwards shift in smartphone screen size is the increasing complex demands we place on our devices. "The devices are more and more effective as media consumption devices, which has helped drive the demand for bigger displays.
"There has been a lot of focus around consuming media on smartphones. It is the device that is always with you, at the end of the day. From an apps perspective, from a service perspective, it is really at the focus of everything. The tablet is still a companion, it is a device that you use in certain scenarios."