The iPhone 5S, rumored to debut on Sept. 10, may sport a convex sapphire-covered home button, if new reports are to be believed.

In other words, recent rumors suggest that the iPhone 5S could launch as quite a major upgrade over the current iPhone 5 flagship. Considering that Apple usually adds minor changes to its iPhone "S" line, this would be intriguing to say the least.

When the company launched the iPhone 4S, many Apple fanboys were left disappointed as the new handset didn't sport any groundbreaking features over its iPhone 4 predecessor. In now seems that things may be different with the iPhone 5 and 5S iterations.

The iPhone 5 already sports a sapphire lens cover, but the iPhone 5S will get a convex sapphire home button as well, said KGI Securities analyst Ming-Chi Kuo, according to 9to5Mac.

The reason for this change is the much-rumored fingerprint scanning technology. The analyst believes that not only will the technology be featured in the iPhone 5S, but it is also the reason behind this redesigned home button.

The iPhone's home button has so far been concave, i.e. curving inwards. The iPhone 5S' sapphire-covered home button, however, would need to be convex, i.e. curved outwards, because the fingerprint technology placed under it would need more space. A concave home button would not leave sufficient space for the technology.

Making a convex home button, meanwhile, would mean that it would be more prone to scratching, thus the choice for sapphire. Compared to plastic, sapphire is a harder and more durable material and would be able to better protect the convex home button.

Apple has yet to officially confirm the iPhone 5S launch date, fingerprint scanning technology or sapphire-covered home button, so take things with a grain of salt for now. On the other hand, Kuo has been accurate on several occasions with his Apple-related predictions. If the rumored Sept. 10 date for the new iPhone unveiling proves to be correct, we'll learn more soon enough.

A fingerprint reader could allow iPhone users to make more secure mobile payments or access their Apple accounts in a safer manner. Smartphones are not just phones anymore, nowadays they keep all sorts of sensitive information and security is paramount. It would make sense for Apple to want to enhance security on its smartphones, but the fingerprint reader and convex sapphire home button are yet to be confirmed.