provides updates to the i OS operating system for the i Phone, i Pad, and i Pod Touch through i Tunes, and since i OS 5.0, over-the-air software updates.
i OS 4 was the first major release to reflect this change.
In June 2007, Apple released the first version of what became i OS – concurrently with the first i Phone.
The final 1.x series release was 1.1.5, released shortly after version 2.0.
July 11, 2008, saw the public release of i Phone OS 2.0, with upgrades through version 2.2.1 made available.
June 17, 2009, was the release date for i Phone OS 3.0.
It was updated through (and including) version 3.1.3 (release date February 2, 2010).The first generation i Pod Touch and i Phone have i Phone OS 3.1.3 as their newest available version.All i OS versions from 3.2 until 4.0 were made specifically for the i Pad.On June 21, 2010, i OS 4.0 (formerly i Phone OS) was released to the public and was made available only to the i Pod Touch and i Phone.i OS 4.0 was announced to have over 1500 new APIs for developers, with the highly anticipated multitasking feature.The i Pod Touch (2nd generation) and i Phone 3G have i OS 4.2.1 as the final version available.