Apple is tight-lipped on its upcoming devices dubbed as the iPhone 6s and iPhone 6s Plus but that doesn't come as a surprise, as the company has the habit of keeping everything under wrap until the eleventh hour. However, several information on the devices have been leaked over the last few weeks, and it is set to have significant feature upgrades over its predecessor, the iPhone 6, if reports are anything to go by.

The release date of the iPhone 6s and iPhone 6s Plus is expected to fall in the month of September by the time its predecessor completes a one-year-cycle but the exact hasn't been leaked until now. Interestingly, M.I.C. Gadget has claimed in a report that the devices will be unveiled on 11 September before releasing on 18. 

The Cupertino giant hasn't revealed anything about the iPhone 6s but going by the reports that have appeared so far, it is expected to have at least five feature upgrades over the iPhone 6.

1) Processor: The iPhone 6 is powered by Apple A8 but its successor is expected to have A9 chip under the hoods.

2) Operating System: the iPhone 6s is expected to coming running on new software iOS 9, while its predecessor runs on iOS 8.

3) Memory: The iPhone 6 comes packed with 16/64/128 GB and 1 GB RAM but its successor is expected to do away with the 16 GB model, which means its base model will come with 32 GB internal memory. The device is also expected to have 2 GB RAM.

4) Camera: The iPhone 6 houses an 8 MP main camera and 1.2 MP front snapper, while its successor is expected to come with 12 MP main camera with feature that can take photos with DSLR quality.

5) Fingerprint Sensor: The iPhone 6s and iPhone 6s Plus are expected to have better fingerprint sensor to provide safer Apple Pay user experience through upgraded Touch ID module.

The iPhone 6s will be 7 mm thick (6.9 mm thick in the iPhone 6), and the iPhone 6s Plus will be 7.13 mm thick (7.1 mm thick in the iPhone 6 Plus), according to a report by M.I.C. Gadget. A report by Business Insider had earlier claimed citing a research data from Citi Research that the devices will come with features like stronger aluminium alloy chassis, Force Touch, and 4.7 and 5.5-inch display.