Developers started receiving notification from the Apple Developer Connection late on Thursday, according to developer sources who spoke with The Mac Observer. The ADC also posted the news to its developer Web site. Apple announced on Monday that iOS 4 had gone “GM,” or Golden Master, the last official version before it was released.
Apple announced what was then called iPhone OS 4 on April 8th at a media event, and a beta Software Development Kit (SDK) for the new OS was subsequently released to developers. On Monday, Apple changed the name of the OS to iOS, or more specifically iOS 4, in order to acknowledge that the OS was now being used on iPhones, iPods, and iPads.
[Update: This article was updated with additional information. – Editor]