watchOS is the mobile operating system of the Apple Watch, developed by Apple Inc. It is based on the iOS operating system and has many similar features.[1] It was released on April 24, 2015, along with the Apple Watch, the only device that runs watchOS. Its API is called WatchKit.
The second version, watchOS 2, included support for native third-party apps and other improvements.[2] It was previewed publicly at WWDC 2015 in June 2015, and released on September 21, 2015,[3][4] delayed seven days[5] by a bug that took longer than expected to fix.[6]
The third version, watchOS 3, was released in beta to developers at WWDC 2016 in June 2016, and released on September 13, 2016. It emphasizes better performance and includes new watch faces and stock apps, including Reminders, Breathe, and Home.
UI overview
The home screen (rendered by and also known as “Carousel”)[1] is composed of circular applicationicons, which can be zoomed in and out with the Digital Crown and dragged and launched by touching the display. Many of the apps are miniaturized, simplified versions of their iOS counterparts.
Glances provide fast access to a summarized view of the most popular native or third party applications used on Apple Watch.[7] The glance view is opened with a swipe up gesture from the watch face screen. With watchOS 3, Glances will be replaced by a Dock of commonly used apps invoked by pressing the side button. Swiping up from the bottom now brings up solely a redesigned Control Center.
Different actions and options appear depending on if the user taps or deep presses which an Apple Watch detects with its pressure-sensitive (Force Touch) Display.[8]
Allows the Apple Watch to act as a nightstand/alarm clock when the watch is charging at night and is turned horizontally while being placed on a table or other surface. Users can look at the time just by tapping the Digital Crown. When an alarm comes on, the Digital Crown can be used to snooze the alarm and the side button can be used to dismiss it.
New Watch Faces and timekeeping features
New 24 Hour Time-Lapse videos of Hong Kong, London, Mack Lake, New York, Shanghai, and Paris. These watch faces allow users to set the backgrounds of different cities as the user’s watch face. As the day moves on, the watch face represents a different time of day in the city. For example, if it is nighttime, the watch will show a skyline of the city at night.
Users can also set a particular photo or their entire photo gallery as the watch face, including support for Live Photos.
Time Travel
A new mode called Time Travel is available in which a user can use the digital crown to scroll forward/backward in time. This allows the user to see upcoming or past calendar events and alarms they have set.
9 new colors to customize watch face, and a new multicolor Modular face.
Third party complications.
Complications will be available from third-party developers which allow users to do things such as check flight status or charging level of electric cars
New Beats 1 button to start playing the 24/7 radio station
New Quick Play button to play a variety of songs from Apple Music
Other improvements
Reply to emails using dictation, emoji, or smart replies customized specifically for email
Make and receive calls using FaceTime audio
Support for Wi-Fi calling without iPhone in proximity on participating carriers
Activation Lock prevents anyone from activating your Apple Watch without your Apple ID and password
New developer capabilities including
Native SDK to build faster and more powerful apps running natively on Apple Watch
Access to accelerometer to more granularly track your motion
Access to heart rate sensor for use during a workout
Access to microphone and speaker to record and play audio
Access to the Taptic Engine with 8 different types of Haptic feedback
Access to the Digital Crown for more precise controls
Ability to play video directly on Apple Watch
Support for running apps without iPhone in proximity, including access to networking capabilities when connected to known Wi-Fi networks
Complications on the watch face
Workouts from apps can be counted towards Activity rings
Workouts from apps can be included in Activity app on iPhone
New support for system language in English (India), Finnish, Indonesian, Norwegian, and Polish
New support for dictation in Dutch (Belgium), English (Ireland, Philippines, South Africa), French (Belgium), German (Austria), Spanish (Chile, Colombia)
New support for smart replies in Traditional Chinese (Hong Kong, Taiwan), Danish, Dutch, English (New Zealand, Singapore), Japanese, Korean, Swedish, Thai
Provides faster access to apps by creating a dock which can accommodate up to 10 apps which will keep running in the background for instant access.
The dock can be invoked using the side button next to the digital crown.
Control Center
Provides support for an all-new Control Center which can be invoked by sliding up from the bottom of the screen.
New Watch Faces.
Adds new watch faces and adds support for switching between them by swiping to the left on the watch screen.
Activity/Workouts
Adds support for sharing activity with friends using iMessage or other messaging platforms.
Adds support for tracking movement of people in wheelchairs, displaying a “Time to Roll” reminder rather than “Time to Walk” as watchOS 2 did.
It is now possible to see 5 different workout metrics all at once. These include distance, pace, active calories, heart rate, and elapsed time.
Adds support for pausing a workout when stopped at a stoplight.
Support for a new Breathe app which will guide users through a set of deep breaths to help them be more relaxed.
Messages
Adds support for the all-new messaging app which will also be present in iOS 10. This includes features such as setting off fireworks, sticking stickers, sharing a secret with invisible ink, or replying in your own handwriting or scribbling letters on the display and letting Apple Watch turn it into text.
HomeKit
Adds support for an all-new Home app which is a centralized place to control all HomeKit accessories.
SOS
Adds support for a feature called SOS which allows a person to contact authorities by holding the side button for 5 seconds.
Mac Unlock
Alongside macOS Sierra, the Apple Watch running watchOS 3 can now allow users to bypass the unlock screen on their Mac by allowing the Mac to detect their Apple Watch and unlock the Mac.
