After the (relatively) major design upheaval of 2020, when the iPhone range switched from curved to squared-off edges, the consensus among pundits is that this year's new models will look largely the same as their predecessors, with Apple's engineers focusing instead on internal upgrades - such as the A15 processor.

That theory has now received a boost. Newly published images of iPhone 13 'dummies' - non-working prototype units used to test compatibility with cases and other accessories - appear to indicate that Apple will use a mostly unchanged chassis this autumn, while still revealing a few intriguing tweaks to the design.

The well-known technology leaker Sonny Dickson published the images on Twitter, claiming they show what this autumn's 13-series models of iPhone will look like.

As Dickson points out, the single biggest (visible) change compared to the current models is that the camera module has become slightly larger, which is in line with previous rumours.

This is a controversial theory, to say the least, since many users already find the protruding camera module annoying, and prone to scratching against flat surfaces when the iPhone is put down on a table or desk. In practice, however, most iPhones are kept in a case which solves the problem.

The configuration of the lenses on the 13 and 13 mini models is also different to that of the 12 and 12 mini, arranged diagonally across the module rather than vertically above one another.

The other significant design change expected for the 13-series update is the shrinking of the screen notch, but that isn't something that would be visible on a dummy unit.

What you can see from a dummy is the dimensions of the screen - but even that is not visible here because Dickson has only published a photo of the units' backs. But based on the size of the dummies themselves the screen sizes are probably unchanged.

Expect two models with 6.1in displays (iPhone 13 and iPhone 13 Pro) as well as a smaller one at 5.4in (13 mini) and a larger one of 6.7in (13 Pro Max). Despite the seeming acknowledgement that the iPhone 12 mini was an unsuccessful experiment, and contrary to our advice, Apple is going to give the mini form factor one last try.

As for the reliability of the source, Dickson is currently rated as 71.4% accurate by AppleTrack, so there's a decent chance these images are genuine.

The new models will probably be launched in September. We can expect plenty more rumours before we get to that point; all of the important and interesting rumours will be reported in our iPhone 13 news hub.

One way we think the iPhone 13 could look different is the colour. Read about the possible colours Apple might choose here: iPhone 13 colour change could be most significant design difference.

If you need to buy an iPhone before then, check the lowest prices available in our guide to the best iPhone deals.

This article originally appeared on Macworld Sweden. Translation and additional reporting by David Price.