watchOS is the operating system installed on all Apple Watches. It manages the apps on the device, but has plenty of built-in features of its own, which is why we're looking forward to 2018's watchOS update so keenly. What features will watchOS 5 bring to our Apple Watches, and when it will be released?

In this article we round up all the rumours, hints, clues and leaks about the upcoming launch of watchOS 5.

Release date

watchOS 5 will be announced at WWDC in June 2018, and roll out as a free update to compatible watches in autumn (probably September) 2018.

Between the two dates a series of beta versions will be made available for those who want to test it out ahead of the release. Most likely this will be limited to developers only; unlike for the other three OSes, Apple hasn't yet allowed public betas for watchOS.

These days Apple follows a predictable pattern with its operating system updates, so we're pretty confident about this schedule.

watchOS 5 release date & new features rumours

New features

watchOS updates sometimes make significant changes to the interface and the way you manage and interact with your apps - such as watchOS 3's hugely important remapping of the side button from contacts to the new app dock - but the hype and column inches will inevitably focus on the new features.

It's early days to be predicting what watchOS 5 will offer in this regard, but here are a few things we're hoping for:

Face ID

The way Apple rumours work, a lot of the time, is that a feature appears on one of the company's products and then everyone predicts that the same feature will then appear on all of the others - hence the rumours of iPhones getting Digital Crown dials and Apple Pencil compatibility, and now everything else getting Face ID.

watchOS 5 release date & new features rumours: Face ID

Could Face ID work on the Apple Watch? Conceivably it could, but like on the iPhone X it would require specially update hardware. The Apple Watch doesn't have a camera at present; but if (as is consistently rumoured) the company add a FaceTime camera to the Apple Watch Series 4 this could be combined with the necessary array of sensors that Face ID requires.

But the other problem is that the Apple Watch has far less need of a biometric unlocking tech than the iPhone. Apple Watches don't have Touch ID; you just unlock them with a code when you put them on in the morning (or even bypass this by putting on the watch and then unlocking the paired iPhone, if you've got that feature activated). Face ID would be used for unlocking purposes once a day, and that hardly justifies the inclusion of a lot of expensive high-end tech.

There's always Animoji, of course, but it seems like a long shot.

Customisable Control Centre

These days you can customise the settings and toggles that appear in the iOS Control Centre, and change the order they appear in. watchOS's Control Centre is far simpler, but it would still be handy to have some scope for change.

Many people don't use the torch feature, for instance, while others can't see the point of Cinema Mode - yet both have a place in the top six 'above the fold', ie they are immediately visible when you swipe up. It would be useful to have the option of swapping one of these with Do Not Disturb, which is below the fold, or removing them entirely. And wouldn't it be nice to get a brightness control here, instead of having to control from the iPhone?

Randomised watch faces

We love the Toy Story animated watch faces in watchOS 4 (which are far more interesting in the near-static Mickey and Minnie faces), but what we particularly love is the Toy Box option. Instead of picking which character you want, this makes the watch display a randomly chosen character (and animated scene) each time you raise your wrist. It's also possible to have a different image appear each time if you go for the Photos face.

watchOS 5 release date & new features rumours: Toy Box

We'd like to see this concept extended into other areas. The time-lapse photos of city skylines are good faces too, but we get bored of always seeng the same one, so a randomised selection would be an improvement. Same for the kaleidoscope faces.

New watch faces

Speaking of faces, there are also calls for more choice beyond what Apple itself offers. There are faces from Hermes and Nike, but people would like to see more.

How about a watch face store for the Apple Watch?

To see what you can do at the moment, read: How to change Apple Watch faces.

watchOS 3 release date & new features

Sleep tracking

Many fitness trackers and smartwatches feature sleep tracking functions that'll monitor your movement while asleep and offer you some kind of stat reflecting your sleep when you wake up - a feature that up until now has been missing from the Apple Watch (other than in the form of third-party apps).

Not for much longer, though, if a report is to be believed. Bloomberg claims that Apple is working on a new app that tracks a user's sleep. Apparently this feature will be supported across all existing models of Apple Watch.

The problem here has always been that sleep tracking required the watch to have enough charge to be used overnight. The Series 2 has two-day battery life, but other models offer less, and most watch users plug in their watch overnight, every night.

One saving grace is that it doesn't take long for the Apple Watch to charge, so owners keen to track their sleep could charge the watch during the evening before bed, for example.

In the meantime, get a good night's sleep with our guide to the best iPhone sleep apps.

Always-on time

This is one of the most requested features of the Apple Watch. It seems preposterous that a watch wouldn't be able to show the time all the time.

Apple's decision not to have a watch face always on is seemingly to preserve battery life, but there are plenty of smartwatches on the market that do permanently tell the time so Apple looks remiss by not offering it.

Multiple devices

You can now automatically unlock your Mac with your Apple Watch, how about your iPhone and iPad?

It would also be useful if you could sync your Apple Watch with more than one device - your iPhone and your iPad, for example.

New Apple Watch apps

We'd like to see the Notes app arrive on the Apple Watch. While it's unlikely you'll be writing (or rather dictating) long notes on the Apple Watch, it would be useful to be able to access your existing Notes on that device.

If you're like us, Notes tends to be a go-to for any piece of information you want to have at your fingertips, so having access to this on your watch could be useful.

Another app people want to see make its way to the Apple Watch is the Podcast app, while being able to listen to audiobooks in iBooks would also be welcome. Finally, how about the calculator app on the watch?

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

Which Apple Watches will be able to run watchOS 5?

We suspect that the first-gen Apple Watch is going to miss out, since our model suffered a slight slowdown after updating to watchOS 3 and a fairly pronounced one for watchOS 4 - we doubt it's got the legs for another major update.

If our hunch is correct this will be the first watchOS release to be limited to certain models only.