You’ll find some other thicknesses spread throughout the flagships, with curved bodies blowing out the sizes to 9 to 11mm, but 7mm tends to be the rough average for keeping thicknesses down. Hey, Apple’s previous model — the iPhone 6 — was a little slimmer again, getting down to 6.9mm.

When you think about it, though, 7mm isn’t much, and there have even been phones that have managed to get lower. Oppo’s R7 did that last year, achieving 6.3mm, making it positively slim.

One thing worth noting is thickness, and the Oppo R7 (left) beats the Apple iPhone 6 (right), though it's a slim win.

Oppo’s R7 size of 6.3mm (left) beats the Apple iPhone 6’s 6.9mm (right), though it’s a very slim win.

But what if you still want thinner again?

If you want to start pushing to even slimmer sizes, you need to start thinking about getting rid of ports, and the 3.5mm headphone jack — that trusty headphone port — is probably the one to go.

Not only would the 3.5mm jack’s removal free up space for other parts or even allow for a bigger battery — because every bit helps! — but it’s also not as big of a deal given how many Bluetooth headphones are available on the market.

apple-iphone-6-plus-review-2014-05

Furthermore, Apple’s Lightning port on the bottom also supports headphones, provided you have the right sort, of course.

Few own them, but if you happen to have Lightning-compatible headphones, you’ll find you can plug them right in, getting your audio from the digital connector, which would be super handy the moment Apple decides to support high-res audio formats natively, though it doesn’t at the time this article was published.

If Apple were to take this path, though, it wouldn’t be the only one, and the aforementioned Oppo tried it in a phone last year, also.

Oppo’s R5 may not be a phone we’d recommend, but you had to give the company credit for trying something different, cutting out the 3.5mm headphone hack and managing to get the metal and glass R5 smartphone down to an insane 4.85mm, making it one of the thinnest smartphones on the planet.

Its battery life wasn’t very compelling, and neither was its fixed memory, plus the microUSB to 3.5mm headphone converter that it came with didn’t work with most of the headphones we tested it with, which is a pretty astonishing oversight, but it was still a neat attempt at something Apple may end up trying this year in the iPhone 7.

Curious as to just how thin the super-thin Oppo R5 is? Here it is sitting next to the 6.9mm thick iPhone 6. There's a separation of 2mm, and yet it doesn't look like it.

Curious as to just how thin the super-thin Oppo R5 is? Here it is sitting next to the 6.9mm thick iPhone 6. There’s a separation of 2mm, and yet it doesn’t look like it.

Yes, if the rumours are true, the seventh generation of the iPhone body change (which would technically be the 13th iPhone) may end up getting slimmer at the expense of the 3.5mm headphone jack, shaving off at least one millimetre and possibly cutting to between 5 and 6mm.

If that were to happen, we suspect Apple would actually also be a first in another way, with it being the first company to bundle in Bluetooth earphones with its smartphone, and that wouldn’t be a bad thing.