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
IPhone accessories for phone calls and voice control of certain devices. Users can adjust volume, control music and video playback (play/pause and next/previous,) and record voice memos on supported iPod and iPhone models and Mac computers. There have been many reports of moisture problems with the remote/mic earbuds. The original iPhone and iPhone 3G came with the iPhone Stereo Headset, a push-button and microphone on the right side of the headphones (there is no volume control, and only limited control of calls). A series of docks released for the iPhone 5, 5s, and 5c, were announced and released on September 10, 2013.