This refers to the fourth major release of the mobile operating system developed by Apple Inc., primarily for its iPhone and iPod Touch devices. It succeeded the iPhone OS 3 and brought several key features that significantly improved the user experience on these devices. As an example, consider the introduction of multitasking, allowing users to switch between applications without losing their place.
The significance of this particular version lies in its impact on mobile computing. It marked a pivotal point in the evolution of mobile operating systems, bringing features previously found primarily on desktop computers to a handheld device. Benefits included increased user productivity through multitasking capabilities and a more organized home screen through the introduction of folders. Historically, it represented a key step in establishing a dominant position in the mobile market for Apple.