iOS 9 (Monarch): Apple's 2015 mobile operating system

Main features

The update added several visible changes for everyday users and new capabilities for developers. Prominent user-facing additions included a redesigned reading and news aggregation app, upgrades to built-in apps, and expanded multitasking on tablets.

• News app: A new curated reading experience replaced the earlier Newsstand model and offered personalized article suggestions and native multimedia layouts in the News application.
• Notes: Enhanced note-taking with rich text formatting, checklists, photo and drawing support, and better organization tools.
• Maps: Improvements such as transit directions in selected cities and better point-of-interest information.
• Siri & Spotlight: A more proactive assistant surfaced suggestions and contextual information; Spotlight expanded search and suggestion capabilities (Siri and Spotlight enhancements).
• iPad multitasking: New multitasking modes for iPad included Slide Over, Split View and Picture in Picture to improve productivity (iPad focused features).

Technical and developer changes

iOS 9 introduced several under-the-hood technologies meant to reduce app size and improve performance. "App Thinning" allowed developers to deliver device-specific app slices and use on-demand resources; Bitcode enabled new compilation workflows. A new Low Power Mode gave users a simple way to extend battery life at the cost of reduced background activity. The platform also reduced the space required for updates and offered system-level optimizations that benefited older hardware.

Release, updates and support

After its September 2015 debut, Apple delivered multiple point releases to add features and fix issues. The iOS 9 series received security patches and maintenance updates; later in its lifecycle Apple produced smaller follow-up releases for devices that could not move to newer major versions. The final widely referenced maintenance build for older, unsupported devices was 9.3.6.

Significance and legacy

iOS 9 is remembered as a refinement release that prioritized robustness, battery life and productivity enhancements—particularly on iPad—rather than dramatic visual change. Its multitasking additions and App Thinning laid groundwork for later iPad productivity features and more efficient app distribution. As part of the continuum of iOS releases, iOS 9 helped shift attention toward performance and the practical needs of users in everyday use.

For further reading about Apple's mobile platform and related topics, see general resources on iOS, system design and app distribution methods (operating system design), the News platform (News), assistant and search capabilities (Siri and Spotlight), and iPad productivity features (iPad).