iOS 12 is the twelfth major release of iOS, released on September 17, 2018, with the iPhone XS generation. It was Apple's public act of contrition for iOS 11: features were deliberately deferred in favor of performance and reliability, with the gains aimed squarely at old hardware — apps launching up to 40% faster, the keyboard 50% faster, and the camera 70% faster on devices like the iPhone 6 and 5s. The release that made five-year-old iPhones faster became, by reputation, the best software gift Apple ever gave its installed base.

Its headline features addressed the era's anxieties: Screen Time quantified and limited device use amid the "smartphone addiction" debate, grouped notifications tamed the lock screen, and the Shortcuts app (from the acquired Workflow) brought user automation into the OS.

Screen Time with app limits and downtime; Shortcuts and Siri Suggestions; grouped notifications with instant tuning; Memoji and camera-effects Messages; Group FaceTime (12.1, up to 32 participants); ARKit 2 with shared experiences and the Measure app; and refreshed Stocks, Voice Memos, and Apple Books. Later point releases quietly stretched further than any before: 12.5's builds delivered pandemic-era Exposure Notifications and security fixes to A7/A8 devices through January 2023.

Every iOS 11 device — iPhone XS/Max/iPhone XR back through the 2013 iPhone 5s, iPad Air and later, and the sixth-generation iPod touch. Nothing was dropped, and the old devices ran better — the release's whole thesis.

iOS 12 rehabilitated the platform's quality reputation and set the modern precedent that a major iOS version can be a maintenance gift rather than a feature race — a genre Apple has revisited whenever the bug ledger grows. Screen Time made digital wellbeing a standard OS category industry-wide, Shortcuts grew into the automation spine later harnessed by Apple Intelligence, and its four-plus years of security updates for 2013 hardware set the support-longevity record the iPhone 6s era then extended.