watchOS is the operating system of the Apple Watch, developed by Apple Inc. It is based on iOS, the operating system used by the iPhone, and has many similar features. It was released on April 24, 2015, along with the Apple Watch, the only device that runs watchOS. watchOS exposes an API called WatchKit for developer use.
The second version, watchOS 2, included support for native third-party apps and other improvements, and was released on September 21, 2015. The third version, watchOS 3, was released on September 13, 2016, to emphasize better performance and include new watch faces and stock apps. The fourth version, watchOS 4, was released on September 19, 2017. The fifth version, watchOS 5, was released on September 17, 2018, to add more third-party support and new workouts, along with the "Walkie-Talkie" feature. The sixth version, watchOS 6, was released on September 19, 2019. The seventh version, watchOS 7, was released on September 16, 2020, to support handwashing and sleep tracking. The eighth version, watchOS 8, was released on September 20, 2021, with updates in health monitoring, visuals, and apps. The ninth version, watchOS 9, was released on September 12, 2022. The tenth version, watchOS 10, was announced on June 5, 2023 at WWDC 2023 and will be released in September 2023.
The home screen (rendered by and also known as "Carousel") is composed of circular application icons, which can be zoomed in and out with the Digital Crown and dragged and launched by touching the display.
Prior to watchOS 3, Glances provided fast access to a summarized view of the most popular native or third-party applications used on Apple Watch. The Glances view was opened with a swipe-up gesture from the watch face screen. With watchOS 3, Glances were replaced by a redesigned Control Center – much like the one in iOS. The friends menu, invoked with the side button, now acts as a dedicated dock for apps.
Different actions and options appear depending on whether the user taps or deep-presses, which an Apple Watch detects with its pressure-sensitive (Force Touch) Display.