IPhone OS 1

iPhone OS 1 is the first major release of iOS, Apple's mobile operating system. No official name was given on its initial release; Apple marketing literature simply stated that the iPhone runs a version of Apple's desktop operating system, macOS, then known as Mac OS X. On March 6, 2008, with the release of the iPhone software development kit (iPhone SDK), Apple named it "iPhone OS" (they later went on to rename it "iOS" on June 7, 2010). It was succeeded by iPhone OS 2 on July 11, 2008.
The iPhone OS 1.1.3 update cost $19.95 for iPod Touch users.
Apps.
Third party apps were not available at the time of the iPhone's release. Starting with iPhone OS 2, third party apps could be installed from the App Store.
History.
Introduction and initial release.
iPhone OS 1 was introduced at the Macworld Conference & Expo keynote address by Steve Jobs on January 9, 2007, along with the original iPhone. At the time, Jobs only said the iPhone ran "OS X".
iPhone OS 1.0 was released, alongside the iPhone, on June 29, 2007.