WatchOS

watchOS is the operating system software of Apple Watch, derived from iOS. The software can be updated by a paired iPhone with the Apple Watch app or directly from the Apple Watch. The current version of watchOS is 6.2.6.

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

watchOS 2
watchOS 2 is based on iOS 9 and was announced on June 8, 2015 at the 2015 Worldwide Developers Conference.

watchOS 3
watchOS 3 is based on iOS 10 and was announced on June 13, 2016 at the 2016 Worldwide Developers Conference.

watchOS 4
watchOS 4 is based on iOS 11 and was announced on June 5, 2017 at the 2017 Worldwide Developers Conference.

watchOS 5
watchOS 5 is based on iOS 12 and was announced on June 4, 2018 at the 2018 Worldwide Developers Conference.

watchOS 6
watchOS 6 is based on iOS 13 and was announced on June 3, 2019 at the 2019 Worldwide Developers Conference.

watchOS 7
watchOS 7 is based on iOS 14 and was announced on June 22, 2020 at the 2020 Worldwide Developers Conference. Developers discovered that early pre-release versions contained code for a "Kids Mode" that uses different metrics for activity tracking of young users. However, this feature has not yet been implemented as of the developer beta.