It's rumoured that Apple will launch its Apple Watch Series 3 later this year. But you can get a bunch of new features - such as a range of new workouts and workout labels - for your existing Apple Watch before then for free, thanks to the new watchOS 4 operating system software.

We got our first look at watchOS 4 at WWDC 2017 on 5 June, and the sixth beta is available to download now. The final official version of watchOS 4.0 is expected to launch some time in the autumn. Read on to find out about watchOS 4's release schedule, the new features it will bring to your Apple Watch and the changes added in each new beta.

If you're thinking of buying an Apple Watch, by the way, you should read our Apple Watch buying guide 2017 and take a look at the best Apple Watch deals.

Release date

watchOS 4 will become available for general download this autumn, around September. In Apple's Q3 2017 financial earnings call on 1 August, Tim Cook looked ahead to the update and said the company had a "very exciting fall ahead".

He added: "Apple Watch will become more intelligent than ever this fall with watchOS4, featuring a proactive Siri watch face, personalised activity coaching, and an entirely new music experience. watchOS 4 also introduces GymKit, a groundbreaking technology platform to connect workouts with cardio equipment."

We saw a preview of watchOS 4 on 5 June at WWDC 2017. After the announcement, watchOS 4 went into a beta testing phase which will last for several months before the finished software is launched to Apple Watch owners at large.

Developers can download a beta version of watchOS right now: in fact, the sixth developer beta has been rolled out. But there's not been a public beta of watchOS for non-developers, as there has been for iOS 11. Here's how to install the watchOS 4 beta. We discuss the changes added in each beta in the next section.

watchOS 4 beta releases

There have been six betas so far:

watchOS 4 developer beta 6

Beta 6 arrived on 14 August and at time of writing is the latest version of watchOS 4. It's build 15R5357b. Now that we're so close to launch Apple is making very subtle changes and fixes with each beta, and this one doesn't contain all that much to thrill the layman - mostly patches to bugs.

watchOS 4 developer beta 5

The fifth beta dropped on 7 August.

iDownload Blog spotted a colourful new 'multiple notifications' icon, and a rearranged layout for the Control Centre; the 'Ping iPhone', for example, gets a slightly higher prominence. 9to5Mac reckons this is the first beta to include the promised full-screen celebratory visual effects when hit landmarks in Activity. And Neowin thinks there may be an issue with pool workout accuracy.

watchOS 4 developer beta 4

Developer beta 4 was rolled out on 24 July alongside iOS 11 developer beta 4. The biggest change in this beta appears to be battery performance: some developers are reporting up to an extra hour of battery life with this beta. We suspect that this is more of a fix to previous issues in beta 3 (discussed below) than a major leap forward, but we'll take what we can get.

Forbes reports that more jellyfish have added to the gallery of moving watch faces, and that a big that stopped Mikey Mouse speaking the time for some users seems to have been fixed, although Minnie remains unreliable for some. The Toy Story faces still don't say anything.

watchOS 4 developer beta 3

This was rolled out on 13 July. It's pretty short on major changes since we're getting closer to the final version, but there are some cosmetic changes you'll notice - the spinning firework animation that pops up in Activity when you close a ring now works, for instance - and of course some crucial if boring big fixes.

iDownloadBlog has made a video of the changes, and warns that it's a battery killer.

watchOS 4 developer beta 2

This came out on 21 June. It added the Toy Story watch faces, which weren't available in the initial beta, and fixes a wide range of bugs that have been spotted so far. 9to5Mac has the full release notes.

watchOS 4 developer beta 1

The original developer beta of watchOS 4 was launched on 5 June, the same night as the WWDC keynote when it was first announced.

When will the watchOS 4 public beta come out?

We don't think there will be one, although that hasn't been officially confirmed one way or another. There wasn't a public beta of watchOS 3, and you'll note that the Apple Beta Software Program page doesn't mention watchOS. (It does mention iOS, macOS and tvOS.)

watchOS 4 rumours: WWDC 2017

New features

Here's a rundown of the new features watchOS 4 brings to your Apple Watch.

Siri watch face

We're going to start with some new watch faces. Which might sound superficial - but it really isn't. At least this first one isn't.

A new 'Siri face' will display information personal to you using machine learning, similar to the proactive functionality and contact suggestions in iOS. (Which in our experience are okay but not spectacular, although these things are improving all the time.) Does this mean that Siri on the Watch is going to work when you're offline? Or can it work based entirely on the information available on-device?

watchOS 4 new features: Siri face

The Siri face displays information using machine learning, to match your routine - so you'll see the information and app shortcuts that are most relevant to your current needs.

You can rotate the Digital Crown to scroll vertically through the various notifications and apps on the face.

Other new faces

Apple also revealed two other groups of watch faces. First up is the kaleidoscope face, which you can rotate using the Digital Crown, producing a trippy effect. The visual elements rotate and change shape, just like those weird toys everybody apparently loved in the sixties.

watchOS 4 new features: Kaleidoscope face

There are also new Disney faces, following on from the popular Micky Mouse and Minnie Mouse faces already available. Woody, Jessie and Buzz Lightyear (from Toy Story) are all coming to the Apple Watch.

watchOS 4 new features: Toy Story watch faces

These seem to be a bit more advanced, visually speaking, than the previous faces. Mickey and Minnie were animated, but in a fairly limited way - jiggling back and forth in time with the clock, basically. But the new faces incorporate multiple, longer animations that behave differently each time you rotate your wrist.

Apple called these 'vignettes' - the character climbing on to the watch face from below, for example.

Alongside Woody, Buzz and Jessie, you'll find Bullseye, Hamm, Rex and the Pizza Planet aliens. You can randomise which character appears on your watch by choosing the Toy Box option in settings.

Activity & Workout

Activity (and what we consider to be its companion app, Workout) are almost certainly the most popular apps on the watch. So we were pleased to see that Apple is continuing to tweak and add to these apps. As elsewhere, Apple is gradually increasing the influence of personalisation and machine learning.

The notifications in Activity are now more personalised to you - they'll let you know if you're close to an achievement, for example. And there's 'smart coaching', which again is personalised to you. This will offer monthly challenges, based on your history and activity records.

There's a cool new sparkly animation to celebrate filling your rings in Activity (it looks nice, but may pall after a few months...), and a change to the way pool swim workouts work. Apple says that taking a rest at one end of the pool will automatically be detected and marked as the end of one set of laps and the beginning of another - handy for accurate timings.

Apple has also realised that notifications aren't important during a workout, so Do Not Disturb will automatically be activated when a workout is initiated, and then automatically turn it off once the workout is complete.

Oh, and one last change to the Workout interface: you can swipe left from the workout menu to access music controls. (Why hasn't this been a feature from the beginning?)

Treadmill sync

We're really pleased to see Apple implement two-way data exchange with gym equipment. (The hopeless inaccuracy of treadmill-based workouts has long been an annoyance - when a device with a more accurate record is right there!)

watchOS 4 new features: Two-way data transfer in gyms

You simply need to tap the NFC tag to connect your watch with the gym equipment, although obviously you'll need to find a gym that supports it first. This is likely to take a while to filter out into the world outside California, we'd guess.

New workouts

The implications of the HomePod firmware leak in the summer of 2017 continue to grow. Developers had previously discovered important clues to the design and feature set of the iPhone 8 in the HomePod's code; now they've spotted references to new workout types in watchOS 4, including yoga, wrestling, water polo, water fitness and "dance-inspired training".

watchOS 4 new workouts

However, TechCrunch believes these are new optional labels for new workout types that you program yourself rather than new additions to the default workout list.

Returning to the officially announced features in watchOS 4, there's a new High Intensity Interval Training workout, which is great to hear. This is a demanding and highly effective form of workout that uses heart rate measurements to push you to your limits - we really enjoyed using this with the Moov HR Sweat activity tracker.

watchOS 4 new features: High Intensity Interval Training workout

Music

The Music app on Apple Watch has been redesigned, and looks much better. There's nice album art - you rotate the Digital Crown to scroll through.

(The Digital Crown seems to be getting far more use in watchOS 4 - which is great. It feels like an underused control in watchOS 3.)

The new Music app again tries to anticipate your needs - you'll automatically see music and playlists that you listen to regularly, freshly updated on your watch. It also includes Apple-curated playlists including the likes of Heavy Rotation, Favourites Mix and New Music Mix. Of course, you'll need an active Apple Music subscription to see these option.

The Apple Watch also supports multiple playlists for the first time.

Other changes

There's a new, redesigned dock interface - you can vertically scroll through recent apps using the Digital Crown. (There it is again!)

There appears to be a new News app for watchOS, based on the watchOS 4 demo, but we haven't got any details. It might just be an interface redesign.

There's a new blinking light activated via Control Centre - useful for safety on night runs.

Apple claims you'll see faster app responsiveness and better background app performance.

You'll also be able to pay friends via Apple Pay on the Apple Watch via an Apple Pay Cash account, although it's initially limited to US users only.

Finally, glucose monitoring is coming to the Apple Watch, although there's not much word on the companion hardware that will presumably be required.

Read about the Best Apple Watch games and Best Apple Watch apps for more information about what's currently available.

And for more information about the Apple Watch in general, read our Complete guide to the Apple Watch and our Apple Watch tips & secrets.

Which Apple Watches will be compatible with watchOS 4?

We expect watchOS 4 to be available for first-gen Apple Watch models as well as the more recent Series 1 and Series 2.

If watchOS 4 launches alongside the Apple Watch Series 3 this autumn, it's just about possible that only that device and the Series 1/2 models will be compatible, with the first-gen missing out. But we'd be surprise to see Apple drop software support for a product that would be only two and a half years old; bear in mind that the oldest iPhone that could install iOS 10 when it launched last year was the iPhone 5, which at the time was four years old.