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 OS 2 Apple II and Mac as one of the great revolutions in modern technology. It takes it beyond simple Phone + iPod, or even smartphone, and makes it the leading contender for the next great shift in computing." However, they criticized it for having stability issues and overall sluggishness. "Macworld" said, "The iPhone 2.0 software is full of the kind of refinements that you’d expect from a second-generation Apple product. The iPhone OS still isn’t perfect, and we wish Apple has addressed some lingering shortcomings, but it’s a welcome step-up for what was already arguably the best mobile platform on the