Apple today made watchOS 4.0 available to the Apple Watch Series 1 and Series 2 wearables. The platform prioritizes the heart rate monitor. Apple Watches will now notify people when it senses a high heart rate if owners are not active. The new software can also look for atrial fibrillation and provide health alerts when necessary. WatchOS 4.0 includes the new Siri watch face that contains the owner's personalized data, such as commute times, calendar appointments, reminders, photo memories, weather updates, and more. The kaleidoscope watch face changes over time, and a wider selection of Disney characters are being added as watch faces. Activity notifications will be more personalized, including goal achievements. Apple says the new workout app makes it quicker to start workouts, such as swims, hikes, and runs. WatchOS 4.0 is more compatible with gym equipment for counting reps. The music player now supports multiple playlists and a wider selection of album art for workouts when using Apple EarPods. Moreover, music functionality will be much more accessible within workout apps. Other features include a new flashlight, a blinking light for nighttime visibility, and support for other sensors, such as glucose monitors. WatchOS 4.0 is free to download from Apple.