iOS
iOS is a mobile operating system developed by Apple Inc. for the iPhone, initially released in 2007 as iPhone OS and renamed iOS in 2010. Built on the Darwin (XNU) kernel with a layered architecture and strong security model, it underpins Apple’s smartphone ecosystem, developer tools, and the App Store. Major platform milestones include the launch of the App Store in 2008, the introduction of Siri in 2011, the spin‑off of iPadOS in 2019, and broad feature expansions such as Apple Intelligence and RCS messaging support in iOS 18.