Apple is expected to launch three new iPhones at a special event sometime next month. In addition to the highly-talked about 5.8-inch iPhone 8, the company will also likely launch 4.7-inch and 5.5-inch iPhone 7s and iPhone 7s Plus that are claimed to be conservative upgrades over the existing iPhone 7 models.

Apart from minor internal enhancements, the upcoming iPhone 7s models are expected to look much like their predecessors. However, a new report says that the iPhone 7s will be slightly thicker than the iPhone 7 because of the use of glass, instead of aluminium, on this back.

iPhone 8 concept image
Apple prepones launch of OLED iPhones despite supply constraintsiDropNews

But why would Apple settle for a thicker iPhone 7s body? The answer is wireless charging capabilities. If true, this year's iPhones will experience a shift from aluminium to glass backs to shoehorn wireless charging, a first for Apple's flagship smartphone line-up.

According to a leaked schematic, obtained by German blog Giga Apple, the iPhone 7s may also do away with visible antenna bands, and feature a form factor that will be bigger than that of the iPhone 7 in all dimensions.

The report, which cited sources within iPhone maker Foxconn, said that the depth of the upcoming iPhone 7s will measure 7.21-millimetres, compared to 7.1-millimetres on the iPhone 7. The width also changes from 67.14-millimetres to 67.27-millimetres while the height gets an even slighter increase from 138.31-millimetres to 138.44- millimetres.

However, due to the overall increased thickness, the camera bump in the iPhone 7s will be about a quarter millimetre thinner than that of the iPhone 7.

Apple's iPhone 7
Apple's iPhone 7 as seen on its official website.Apple

When it comes to wireless charging, this is not the first time when Apple's iPhone 7s models are said to come with the new charging capability. In June, Wistron CEO Robert Hwang reportedly revealed that the new iPhone 7s Plus would feature wireless charging.

A set of leaked images of purported iPhone 7s dummy units earlier this month also indicated that the devices would have glass back, and would come with a design to support wireless charging.

Rumours are rife that the iPhone 7s and 7s Plus with LCD screens are likely to arrive in mid-September while the OLED iPhone 8 is not likely to hit stores until late October.