What's new in watchOS 8

Description: watchOS 8 brings all-new opportunities to keep people up to date on their watch face. With new APIs for the Always-On Retina display and updating complications from Bluetooth devices and background delivery of HealthKit data, it's never been easier to keep your app up to date. Learn about region-based user notifications to leverage location in your app. Explore all the new enhancements to SwiftUI and watchOS that will get you excited to build your next Watch app.

Always-on display dimmed state

  • Supported on series 5 and 6
  • in watchOS 7, the always-on state showed your app’s UI blurred with the system time overlaid
  • when you rebuild your app with the watchOS 8 SDK, your app’s UI will now be shown in a dimmed state instead, and is immediately interactive if someone taps the UI
  • You can get notified of of this dimmed state via a new SwiftUI environment property isLuminanceReduced.
  • You can respond to this state by highlighting information that’s especially important, and hiding information that should stay private
  • In the watch simulator, you click the lock button in the simulator window to simulate a wrist-down event (triggering the dimmed state)


  • the transition from active state to the always-on state should feel seamless
  • don’t drastically alter the UI or reorganize information
  • dim non-essential information and elements, to give more prominence to the piece of information you want to stay highlighted and visible
  • if your UI has large elements that are filled with color or imagery, you may want to reduce those elements to be represented with a stroke or dimmed color
  • redact or remove sensitive information
  • reset animations
  • use SwiftUI's TimelineView to tell watchOS 8 that your inactive app needs to update its UI

UI Updates: - Apps with an ongoing, active session (e.g. workout or audio session) can update your UI up to once per second - other apps up to once per minute - assume your app is visible longer than two minutes

HealthKit data

  • background delivery of HealthKit data to Watch apps
  • new results come up to once per hours
  • if you have an active complication, up to four times per hour
  • all received results count against background app refresh budget

Update frequency:

  • immediate for critical data types (fall events, low blood oxygen saturation, heart rate events)
  • hourly or longer for other events


  • from watchOS 4, Bluetooth devices can connect directly to Apple Watch and make use of Core Bluetooth.
  • from watchOS 8, Bluetooth devices can connect during background app refresh opportunities that your app’s complications get when they’re on the active watch face
    • this means that your app’s complications can stay up to date with your Bluetooth device and display updated information throughout the day.
    • Background app refresh gives your app’s complications that are on the active watch face up to four opportunities per hour to connect and update.
    • these opportunities will count against your app’s overall background app refresh budget

Guidance: - connect and process your data within a very short period of time - new expiration handler on WKRefreshBackgroundTask, letting you know when you're about to run out of time


  • new in watchOS 8, region-based user notifications
    • works similarly to iOS:
      • deliver pre-created local notifications
      • "when in use" location permission required
      • limit the number of regions to only include important POIs near someone or locations they’ve shown explicit intent for
  • new Location button, for one-time location authorization without going through authorization prompts each time it’s tapped
  • always-on altimeter API, no need location access

More enhancements

  • respiratory rate API
  • assistive touch
  • large accessibility text size
  • (Xcode 12.5+) Unit testing and UI testing
  • Large titles
  • text input improvements:
    • Scribble or Dictation preference is preserved per app
    • quick access to changing between input types while entering text
    • SwiftUI's .searchable API
    • Swipe actions on List
    • Buttons improvements:
    • new roles parameter to let the system know how to present and handle specific button types (e.g. destructive buttons)
    • new controlProminence view modifier, which will give those buttons an additional haptic when tapped.
    • SwiftUI Canvas for rich programmatic drawing

Missing anything? Corrections? Contributions are welcome 😃


Written by

Federico Zanetello

Federico Zanetello

Software engineer with a strong passion for well-written code, thought-out composable architectures, automation, tests, and more.