According to Apple, the Watch has been a huge success however you measure it. Millions sold, impossibly high customer satisfaction. So there's no reason to think it isn't already well into the design phase for the next generation.

KGI Securites analyst Ming-Chi Kuo claims Apple will focus on design for the first time since the original Apple Watch was announced, and that we could see a 15 percent larger display and a more "trendy" form factor. Kuo also says it will incorporate new health-tracking sensors, and benefit from a boost to battery life.

A new patent spotted by Patently Apple suggests it's planning to bring new features to the Apple Watch that include Face ID. This means your watch will be able to unlock when you look at it.

Yet more patents suggest the new Apple Watch could have a circular design, and respond to motion and gestures.

When is the Apple Watch 4 coming out?

For the last two years, Apple has launched a new version of its smartwatch in September alongside new iPhones. It seems unlikely it will deviate from this pattern in 2018, so if you're already waiting for the fourth-gen Apple Watch, you've got around six months before it appears on shelves.

How much will the Apple Watch 4 cost?

Based on the current prices, we think the Apple Watch 4 will start at £329 for the smaller 38mm version and £359 for the larger model. And those are likely to be the same in US Dollars.

You'll pay more if you want a fancier strap or a higher quality body material. 

It may be more expensive than many Android smartwatches, but the Apple Watch is arguably the best of the bunch.

Apple Watch 4 rumoured features and specifications

As we mentioned above, the Apple Watch 4 could get a redesign with a 15 percent larger (potentially rounded) screen, a new "trendy" form factor, new health sensors and improved battery life.

Looking at patents filed in the past year or so we can also speculate over possible updates to this year's wearable, one of which is the addition of Face ID.

Another focuses on a 'power band' (shown below), which could incorporate batteries to give the Watch extra runtime between charges.

Apple Watch 4 release date, price, specs rumours

A 'self-adjusting strap' could also make the watch more comfortable, easier to put on and - possibly most importantly - allow the sensors to be as accurate as possible. Measuring heart rate is difficult is the watch isn't in close contact with the skin, at least using the current optical methods.

Many thought that the older patent for a modular strap would mean the Series 3 was modular, but it didn't happen. It's possible, then, that the Series 4 could be modular in some way, if Apple hasn't ditched the idea.

Apple Watch 4 release date, price, specs rumours

There are other features, which could be introduced in the Apple Watch Series 4:

  • Sleep tracking
  • Camera
  • Respiration tracking
  • 3D Touch screen
  • Face ID

The Series 3 brought one long-rumoured feature: LTE. That means it can operate to an extent without an iPhone, but you still need an iPhone to set it up in the first place. It's unlikely anything will change in this respect with the fourth-gen Watch, but we can all hope for longer battery life.