WatchOS

watchOS is the mobile operating system developed by Apple for the Apple Watch line. The software can be updated by an iPhone paired through the Apple Watch app, or directly from the Apple Watch. Derived from iOS, the current version of watchOS is 8.1.1.

watchOS 1
watchOS 1 is based on iOS 8.x and was introduced with the original Apple Watch on April 24, 2015. This version introduced watchOS, the operating system for the Apple Watch.

watchOS 2
watchOS 2 is based on iOS 9 and was announced on June 8, 2015 at the 2015 Worldwide Developers Conference. This version introduced more developer tools for third party apps and new native apps specifically for Apple Watch.

watchOS 3
watchOS 3 is based on iOS 10 and was announced on June 13, 2016 at the 2016 Worldwide Developers Conference. This version introduced the Breathe app, instant launch apps, a dock for favorite apps, and a new Control Center.

watchOS 4
watchOS 4 is based on iOS 11 and was announced on June 5, 2017 at the 2017 Worldwide Developers Conference. This version introduced new Siri watch faces, personalized Activity coaching, new measurements in the Heart app, and improvements to music.

watchOS 5
watchOS 5 is based on iOS 12 and was announced on June 4, 2018 at the 2018 Worldwide Developers Conference. This version introduced competitions in Activity Sharing, automatic workout detection, and support for Apple Podcasts.

watchOS 6
watchOS 6 is based on iOS 13 and was announced on June 3, 2019 at the 2019 Worldwide Developers Conference. This version introduced a dedicated App Store inside watchOS, ability to install apps without needing an iPhone, new Calculator, Voice Memos, Audiobooks, Noise, and Cycles app, and Nightstand Mode.

watchOS 7
watchOS 7 is based on iOS 14 and was announced on June 22, 2020 at the 2020 Worldwide Developers Conference. This version introduced sleep tracking, hand washing detection, and new dance workouts. It added support for the Apple Watch Series 6 and the 1st-generation Apple Watch SE, which were released in September 2020.

watchOS 8
watchOS 8 is based on iOS 15 and was announced on June 7, 2021 at the 2021 Worldwide Developers Conference. This version introduced the Mindfulness app, redesigned photos app, new portrait mode watch faces, and ability to find items on Apple Watch. It added support for the Apple Watch Series 7, released in October 2021.

watchOS 9
watchOS 9 is based on iOS 16 and was announced on June 6, 2022 at the 2022 Worldwide Developers Conference. It dropped support for the Apple Watch Series 3 and added support for the Apple Watch Series 8, the 2nd-generation Apple Watch SE, and the Apple Watch Ultra, which were released in September 2022.