iPhone OS 2 is the second major release of what is now iOS, released on July 11, 2008, alongside the iPhone 3G and as a free update for the original iPhone (paid, for iPod touch owners). One feature defines it: the App Store. Native third-party applications, distributed and installed over the air through Apple's curated storefront, transformed the iPhone from a fixed-function device into a platform — and created the modern app economy in the process.

The release was the product of the iPhone SDK, announced that March, which gave developers Cocoa Touch, Xcode tooling, and a 70/30 revenue split that became the industry's reference terms. The store opened with about 500 applications; within a year it passed 50,000, and "there's an app for that" entered advertising history.

Beyond the App Store, iPhone OS 2 aimed at the enterprise: Microsoft Exchange ActiveSync support brought push email, calendars, contacts, and remote wipe, answering the BlackBerry question head-on. MobileMe replaced .Mac for consumer push syncing (with a launch rocky enough to draw a Jobs apology), contact search arrived, and the scientific calculator appeared in landscape. Point releases added podcast downloads over the air (2.2) and Google Street View in Maps.

The launch update itself was turbulent — activation servers buckled on release day, and 2.0's stability on the original iPhone drew months of complaints until 2.1 delivered a broad fix that September.

iPhone 3G, iPhone (1st generation), and both early iPod touch generations. It was the 3G's launch software and the original iPhone's first taste of native apps.

The App Store is the most consequential feature ever added to the platform: it defined how software is bought, sold, reviewed, and gatekept on phones — economics and controversies alike — and every rival platform copied its shape within two years. iPhone OS 2 turned Apple's phone into the foundation of a developer economy now measured in the trillions, a line that runs unbroken to iOS 26.