"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
New Photo of Alleged iPhone 5S Home Button Flex Cable Could Point to Fingerprint Sensor Support
But as noted by Nowhereelse.fr [Google Translate], a new home button flex cable part has surfaced that may show support for the fingerprint sensor. The part contains an identifier of 821-2092-01 in line with Apple's usual part number scheme, and appears to carry a manufacturing date code corresponding to the 29th week of 2013, or mid-July.
The flex cable part is far more complex than that seen in the iPhone 5 or even the alleged iPhone 5S part leaked last month, containing a new square surface as well as several other components that may be related to fingerprint sensor functionality.
Apple routinely alters its combinations of components included on flex cable parts to suit its evolving internal and external designs, but it is not immediately apparent what existing component could account for the features seen on this part, suggesting that they may indeed be for a new feature such as the rumored fingerprint sensor.
Also potentially contributing to differences in part leaks is word that Apple initially did not build the fingerprint sensor into iPhone 5S prototype, instead connecting an external sensor for testing purposes. As a result, the home button flex cable design may have changed over time as Apple worked to move it from an external assembly into the home button.
Finally, early part leaks may have seen some confusion over which parts were destined for the iPhone 5S and which were intended for the lower-cost iPhone 5C, which is not expected to include a fingerprint sensor.
Apple is expected to introduce the iPhone 5S and iPhone 5C at a media event on September 10.
Update: MobilesPie shared photos of a similar part last week, but the retailer selling the part lists it as for the iPhone 5C.