The final release supported on the original i Phone and i Pod Touch is i Phone OS 3.1.3.
i Phone OS 3 was compatible with all i OS devices released up to that time, but not all features were available on the original i Phone.
With the announcement of i OS 5.0 on June 6, 2011, a USB connection to i Tunes was no longer needed to activate i OS devices; data synchronization can happen automatically and wirelessly through Apple's i Cloud service.
Major new i OS releases are announced yearly during the Apple Worldwide Developers Conference (WWDC), and are usually released in September of the same year, usually coinciding with the release of new i Phone models.
As of i OS 4.0, Apple no longer charges money for i Pod Touch updates.
As of 2017, two versions of i OS were never released.