IPhone OS 2 available to the iPhone and iPod Touch. Prior to the public release of iPhone OS 2.0, Apple held a keynote event to announce the iPhone OS Software Development Kit ("SDK") to developers. The most notable feature of iPhone OS 2 was the App Store. Before this feature was introduced, the only way to install custom applications on the device was via jailbreaking, which is strongly discouraged and unsupported by Apple. There were 500 applications available for download at the launch of the App Store, though this amount has grown dramatically since then. Now, the App Store has more than 2
IPod Touch date has been introduced with the same release number of iOS as the contemporary iPhone model. Successive updates to iOS since the initial release in 2007 have released additional features. iPhone OS 2.0, released on July 11, 2008, introduced the App Store, which allowed third-party applications for the first time. iPhone OS 3.0, released on June 17, 2009, added features such as cut, copy, and paste, data tethering and push notification support. iOS 4.0, released on June 21, 2010, introduced iBooks, FaceTime, and multitasking. It dropped support for the first generation iPod Touch. In June 2011, iOS 5, the fifth