Apple's next flagship phone will be called the iPhone 5S
As with the iPhone 5C, mobile phone operator leaks have indicated that Apple is maintaining its current iPhone naming scheme, sticking with the solitary number and variations to denote upgraded iPhone models. Given that the alternative iPhone is highly likely to be called the iPhone 5C, the 5S moniker could be another differentiator for Apple's next flagship phone.
The iPhone 5S will be available in more colours
Ever since the iPhone 3G launched, in 2008, Apple has offered its smartphones in two colours, black and white. Recent part leaks from Apple's manufacturing partners in China have indicated that Apple will launch the iPhone 5S in more colours including a gold, or "champagne", model, which could make sense in terms of Apple's attempt to secure market share in Asia.
Apple will upgrade the camera in the iPhone 5S
It is highly probable, given the competition from the likes of the Samsung Galaxy S4, with its 13-megapixel camera, that Apple will improve the current 8MP camera from the iPhone 5 to at least 13 megapixels.
The iPhone 5S will have almost exactly the same design as the iPhone 5
Apple has a history of redesigning the look of its flagship phone only every other generation, improving the specifications and inner components without altering the case design on the outside significantly. Both part leaks and previous actions suggest that Apple will stay true to form and release the iPhone 5S with improved insides while maintaining the iPhone 5's design with subtle tweaks.
Slightly more speculative
Apple will build a fingerprint reader into the iPhone 5S
Recent rumours have it that Apple may build a fingerprint reader into the iPhone 5S, possibly under the traditional home button, to boost the iPhone's security credentials. In theory, such an addition could allow password-free...