Welcome to the next evolution of Apple Watch.

watchOS 4 may not be a gigantic update for Apple Watch, but it brings a lot of smart additional functionality to Apple's wearable. Here's a quick breakdown of everything that's new and changed in watchOS 4.

Setup

Look and feel

  • New List view option for viewing apps
  • Bigger PIN pad for entering passcode on watch
  • Elimination of most page-based horizontal scrolling
  • Redesign of most apps to embrace iOS's bold text and card-based structure

The Dock

  • All-new Dock vertical design and functionality
  • Dock can have either Favorites or Recents saved — not both
  • Sideways swipe to remove Dock apps
  • All Apps shortcut button at the bottom of the Dock

Control Center

News

  • News app with top 5 stories of the day
  • New redesigned notification cards

Watch faces

  • New Siri face (can display Alarms, Breathe, Calendar, Home, Maps, News, Now Playing, Photos, Reminders, Stocks, Stopwatch, Timer, Wallet, Weather, and Workout)
  • New Kaleidoscope face
  • Turn any photo in iOS 11 into a Kaleidoscope or Photo face
  • New Pixar Toy Story face (Buzz, Woody, Jessie, Toy Box)

Complications

  • Messages now shows unread messages
  • News shows a ticker of latest story
  • Music/Now Playing shows interactive peak meter along with song title
  • Heart Rate displays last heart reading and time interval

Intelligence

  • Music app will display whenever you're playing audio on connected devices (i.e. iPhone, car stereo via iPhone) and is fully controllable; podcast controls supported, too
  • If playing audio in third-party app, and that app has a watch component, watch app's now playing screen will display instead
  • Workout app will display as primary screen when you're working out, and mute all notifications
  • Breathe and stand notifications won't prompt you if Apple Watch thinks you can't benefit (i.e. you're working out, in a car, etc)

Fitness and Activity

  • Health can sync to iCloud in iOS 11 (but Apple Watch still has to sync to iPhone first)
  • Activity provides customized notifications based on your activity level, accelerometer, and time-based data
  • Automatically play music through your headphones when starting a workout (if not already listening to music)
  • New 3D animations for achievements
  • Personalized monthly achievements

Workouts

  • Workout app gets new vertical cards-based interface
  • New HIIT workout
  • Improvements to Pool Swim to track sets and rests, pace per set, and distance for different stroke types
  • Switch exercise types on the fly during an active workout (swap between running, HIIT, cycling, swimming, and more)
  • Change your music's volume and tracks within the Workout app
  • If you're working out at a gym with compatible (read: new and fancy) equipment, you'll be able to wirelessly pair your Apple Watch with the machine to sync up your fitness data and get credit for that awful treadmill run
  • Save Other workouts with custom exercise types and icons

Heart Rate tracking

These features should be available with the release of watchOS 4 for Series 1, 2, and 3 owners; I've heard conflicting reports on whether the original Apple Watch will get anything but the 24-hour scatterplot graph, but we're looking into it.

  • Overall faster readings
  • An overview of your current heart rate, resting rate, walking average, and last recorded exercise
  • A 24-hour scatterplot graph of your recent heart fluctuations along with your most recent reading
  • Alerts if your heart rate peaks when your watch detects no major activity (adjustable based on your fitness level and age)

Music

  • New card-based Music app interface
  • Can no longer browse iPhone's music library except through Siri
  • Now Playing complication lets you control play/pause/speed/volume for any audio on connected external devices (i.e. iPhone, iPhone connected to car stereo, etc)
  • Sync multiple playlists to your Apple Watch (up to 2GB on 8GB; the 16GB Series 3 GPS + Cellular may have a larger option, but I haven't yet tested it)
  • Automatically sync most-played playlists and albums while your watch charges

New developer tools

  • APIs for turn-by-turn navigation alerts and haptics
  • Auto-rotation for content like payments, language translation, photos, and more
  • Audio recording in background
  • Apps can get permission for location directly on the Watch
  • Apps can connect directly to most Bluetooth devices (no cars, sadly) without using an iPhone as a passthrough

Any features I've missed?

Found anything cool about watchOS 4? Drop it in the comments.