It may be several months since the launch of watchOS 4 in September 2017, but Apple's regular incremental update cycle means there's still plenty to talk about.
Here we round up all the latest news and rumours about watchOS 4, and break down its key features.
Apple watchOS 4 at a glance
- Released on 19 September
- Previewed at this year's WWDC in June
- Boasts person-to-person payments and new goal rewards
- Features the Apple Heart Study app that monitors for irregular heart rates
- GymKit lets you pair to exercise equipment for accurate readings
Apple watchOS 4: Latest news
01/12/2017: Apple has launched a new app that allows for the collection of heart rhythm data through the Apple Watch heart sensor, which the company will use as part of its ongoing effort to identify cardiovascular irregularities.
The company first announced it would begin using the Apple Watch as a means of identifying sufferers of atrial fibrillation (AFib), back in September during the launch of watchOS 4. Now the company has released a new app to help launch the study.
Apple is working alongside Stanford University on the Apple Heart Study project, with the goal of providing accurate heart rate data that can be used within the medical community.
AFib is a heart condition that causes an irregular and often abnormally high heart rate in sufferers. While normal resting heart rates will be between 60 and 100 beats per minute, patients with AFib may experience rates considerably higher than 100 beats per minute.
This abnormally high heart rate can lead to dizziness, heart palpitations, or a shortness of breath, and is considered one of the leading causes of stroke in the US. However, in many cases the condition is symptomless and patients are unaware that their heart rate is irregular.
"Working alongside the medical community, not only can we inform people of certain health conditions, we also hope to advance discoveries in heart science," said Apple COO Jeff Williams.
The heart rate is calculated by using LEDs and light-sensitive photodiodes to determine how much blood is being pumped through the wrist, and uses a host of sensors to isolate the heart rhythm from external noise.
Participants in Apple's study will receive notifications on their Apple Watch and iPhone if any irregularities are detected, providing them with a free consultation with a study doctor and an electrocardiogram (ECG)patch for further monitoring. The study is open to any US adult over the age of 22 who owns an Apple Watch Series 1 or later.
Images courtesy of Apple
Apple watchOS 4: release date and pricing
WatchOS 4 won't cost Apple Watch owners a penny; they simply need to download it as normal as with any other operating system update. The official release date is 19 September.
Apple watchOS 4: features
Apple Pay's person-to-person payments
WatchOS 4 will benefit from iOS 11's new person-to-person payments feature within Apple Pay, in a move that makes the Apple Watch more useful in people's daily lives. Not only can users pay with the contactless technology over the counter, but a simple text now sends money to a friendvia Apple's Messages, or even using Siri. "When users get paid, they receive the money in their new Apple Pay Cash account and can use it instantly to send to someone or make purchases using Apple Pay in stores and apps, or transfer it to their bank account," explains Apple.
Activity
Once again, Apple has improved its Activity app with a new iteration. Users close to achieving a goal they've set will wake up to a notification encouraging them to hit it, or receive tips on how to match what they managed to do the day before. The app also introduces personalised Monthly Challenges tailored to the user.
GymKit
WatchOS 4's new app, GymKit, fitness fanatics can pair their Watch with certain gym equipment like treadmills, indoor bikes, and more, with manufacturers currently signed up including Life Fitness and Technogym.
This means that data including burned calories, distance, speed, incline and pace will sync between the Watch and the machine, giving users a more accurate understanding of their workout.
However, without a full list of participating manufacturers (and what gyms have that equipment), it's hard to know how useful GymKit will be in the short to medium term.
Workout
Apple Watch's Workout app gets a revamp in WatchOS 4 as well, introducing new features focused on high-intensity workouts and those swimming lengths of the pool.
Workout can now combine multiple workouts for those training for events like triathlons, so they get their overall calorie consumption and time measurements.
Jeff Williams, Apple's chief operating officer, said: "We've created a truly individualized experience with the smartest Activity and Workout apps, the Siri watch face that shows you the information you need when you need it and we're seamlessly bringing users their favorite music right on the wrist."
Music
Apple has redesigned the Watch's Music app to automatically sync your New Music Mix and Favorites Mix with your most-listened to tunes, with the aim of making those long runs and punishing workouts a little more enjoyable.
New watch faces and bands
For those who like to customise their Watch a little, Apple is bringing some new options in the latest operating system, with a range of characters from theToy Storymovies, letting people choose between Woody, Jessie and Buzz to adorn their wrists. Another watch face, dubbed Kaleidoscope, turns your cover image into a kaleidoscopic pattern that might end up distracting you on a particularly dull afternoon at the gym.
A new Siri watch face powers the display with information that changes depending on the time of day and a user's daily routine, pulling information from the Activity app as well as a user's calendar, alarm, maps and reminders - as well as Apple News headlines.
Summer-styled bands are available now to greet the season, including vibrant new Sports Bands, a yellow Classic Buckle and some Nike Sport Bands. A rainbow Pride Edition nylon band is also available.
