IPhone 4S announced iPhone 5s and iPhone 5c. This was unusual for Apple as an upper case 'S' had been used since the introduction of the iPhone 3GS in 2009. On September 9, 2014, the iPhone 4S was officially discontinued following the reveal of the iPhone 6 and the iPhone 6 Plus. However, 4S production did continue for developing markets until February 17, 2016. On June 13, 2016, following the release of iOS 10, Apple dropped support on the iPhone 4S, making iOS 9.3.5 the last version available for the device. The runs iOS, Apple's mobile operating system. The user interface of
IPhone 5S took rival Android smartphone makers by surprise, particularly Qualcomm whose own 64-bit system-on-chip was not released until 2015. Most reviewers recommended the iPhone 5S over the iPhone 5C which was released at the same time. The 5C retained almost the same hardware as the discontinued iPhone 5, while the iPhone 5S featured substantially improved performance/features thanks to its new 64-bit A7 processor, as well as extra storage space, all for a relatively small additional upfront cost over the iPhone 5C (US$650 versus US$550 in March 2014). This was especially the case when iOS 8 was released and both iPhone 5S