The operating system in Apple's smartwatch. Introduced in 2015, following is a brief summary of watchOS versions. See Apple Watch
watchOS 8 (Fall 2021)
A user's photo can be used as the watch face. Messages support dictation, typing and emojis, and errors can be more easily corrected before sending. The Reflect app offers meditative phrases, and an overnight respiration rate was added. The updated Home app makes it easier to control smart home devices.
watchOS 7 (2020)
Some features require at least Apple Watch series 3 while others require 5 and above. Complications are like widgets that allow apps to display relevant information on the watch face, such as outside temperature, map location or foreign language translator. An iPhone is no longer mandatory for all Apple watch features, and multiple Complications can be displayed. Native sleep tracking and a new fitness app were added. A 20-second hand washing countdown is included, and the noise alert was expanded for headphones.
watchOS 6 (2019)
The app store was added to the watch along with more watch faces, message Animojis and improved health and fitness capabilities. A sound monitor alerts users that the current ambient noise can be harmful. An iPhone 6s or SE with iOS 13 is the minimum requirement.
watchOS 5 (2018)
A walkie talkie was added to send messages to other Apple Watch users via Wi-Fi or cellular. Automatic workout detection that starts tracking if the wearer forgets to start the app. watchOS 5 requires a minimum of an iPhone 5S, iOS 12 and second generation Apple Watch.
watchOS 4 (2017)
More Siri-based watch faces for daily news and reminders, a changing kaleidoscope face and several animated Toy Story faces. Activity apps are enhanced, supporting multiple workouts, more personalized notifications, multiple workouts in a single session and integration with major gym equipment. Music app more integrated with workouts.
watchOS 3 (2016)
A more efficient watchOS 3 debuted with Apple's second-generation smartwatches. New watch faces and several features were added, including more Siri integration, improved social apps and a personal alarm that dials an emergency number.
watchOS 2 (2015)
Released the same year as the first watchOS version, an alarm clock/nightstand mode was added. Siri was enhanced, more watch faces were offered, and third-party apps could run without pairing to the iPhone.