History of Apple Inc.
The first version of the iPhone became publicly available on June 29, 2007 in selected countries/markets. It was another 12 months before the iPhone 3G became available on July 11, 2008. Apple announced the iPhone 3GS on June 8, 2009, along with plans to release it later in June, July, and August, starting with the U.S., Canada and major European countries on June 19. This 12-month iteration cycle has continued with the iPhone 4 model arriving in similar fashion in 2010, a Verizon model was released in February 2011, and a Sprint model in October 2011, shortly after Jobs' death.
IPhone 4S
The iPhone 4S was first shipped with iOS 5, which was released on October 12, 2011, 2 days before the release of the device. The 4S uses iOS 5.1.1, which was released on May 7, 2012. As of September 2015, the device can be updated to iOS 9. It can act as a hotspot, sharing its internet connection over WiFi, Bluetooth, or USB, and also accesses the App Store, a digital application distribution platform for iOS developed and maintained by Apple. The service allows users to browse and download applications from the iTunes Store that were developed with Xcode and the iOS SDK and were published through Apple.