iPhone OS 2 (later called iOS 2) was released on July 11, 2008, alongside the iPhone 3G. It was supported with updates until its final version 2.2.1, which was released on January 27, 2009. This gives iOS 2 a support span of about 6 and a half months with official updates. During this time, it introduced key features like the App Store and enterprise support features.

If the question was aimed at how long iOS versions generally receive updates or support by Apple, modern iOS versions usually receive support for several years, often around 5 to 8 years depending on the device and iOS version history. However, specifically for iOS 2, the update cycle was short, roughly half a year.

Please let me know if the question refers to something else about iOS 2 or iOS in general.