The original iPhone OS 2 (later called iOS 2) was released on July 11, 2008, alongside the iPhone 3G. It was the first version to support third-party apps via the App Store and was available as a free update for first-generation iPhones and as a paid update for iPod Touch users at $9.95.
If the question instead relates to the current iOS 26, it is being released on September 15, 2025, with rollout times depending on the region and timezone.
Please clarify if more detailed information about either iOS 2 from 2008 or iOS 26 from 2025 is needed.