The Apple Watch Series 4 has been announced, with a new edge-to-edge screen and black ceramic back - over 30 percent larger screens are on both 40 and 44mm models.

It has a slimmer design, while the UI has also been redesigned to take advantage of the new screens

The Apple Watch Series 3 was a critical hit, but Series 4 changes it up significantly. 

Apple Watch Series 4 price and release date

  • 21 September release date
  • Available in the UK from Vodafone and EE

The Apple Watch Series 4 release date will be 21 September and it will be available on cellular on EE and Vodafone in the UK. You can pre-order from Friday.

Apple Watch Series 4 starts at £399/$399 for the 40mm version (£499/$499 with cellular) and £429/$429 (£529/$529) for the 44mm one. 

Apple Watch Series 3 is now available at the new starting price of £279/$279 - it looks like Apple Watch Series 1 has now been discontinued. 

Nike+ and Hermes versions will be available as before. The Apple Watch Nike+ costs the same as the new Apple Watch Series 4.

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Apple Watch Series 4 design and display

  • 30 percent bigger screens
  • Both are bigger - 38 becomes 40mm, 42 becomes 44

The Apple Watch Series 4 has that new edge-to-edge screen and black ceramic back. Both 40 and 44mm models (yes, they're both bigger) feature 30 percent larger screens.

It's available in three aluminium finishes, gold, silver and space grey plus two stainless steel finishes. There's also a new gold stainless finish. All older bands fit this new watch. 

Apple Watch Series 4 specs

  • Double the performance of Series 3
  • Call clarity better, louder speaker, too 

The new Watch is based on Apple's S4 platform with a 64-bit dual-core performance and should offer double the performance of Series 3. 

The digital crown has been re-engineered to give you taptic feedback, while there's also a new speaker that's 50 percent louder especially for clearer Siri requests. The microphone is now as far away from the speaker as possible to improve phone calls. And thanks to the ceramic back, phone call clarity is better, too. 

Apple Watch Series 4 has the same 18 hour battery life as Series 3. The GPS tracking battery life is now increased to six hours, a welcome addition. 

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Apple Watch Series 4 software

  • Will run watchOS 5 with a redesigned interface
  • Lots of new health features

The new Apple Watch software update - watchOS 5 - was announced at Apple's Worldwide Developer Conference (WWDC) in early June. This will be available on 17 September for users of older Apple Watches.

The UI has also been redesigned to take advantage of the new screens, with new complications and a brand new watch face with up to 8 complications. It's even possible to have pictures of your key contacts on the face of the watch. App icons and fonts are bigger and easier to read.

watchOS 5 includes a lot of new Activity and Workout features, the Walkie Talkie app and interactive notifications. Find out more about watchOS 5 features

The Watch adds to its health capabilities by being able to detect falls using the accelerometer and gyroscope. Nice to have, unless you often pass out when drunk. You'll get the ability to call emergency services or it will auto-call within 60 seconds and send a message to your emergency contact. 

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As well as the high heart rate notifications you get normally (and that people often shared during key moments of the World Cup), Apple Watch can now detect when your heart rate is too slow or irregular "suggestive of atrial fibrillation".

You can also take an ECG of yourself using electrodes in the back of the watch and on the digital crown. Whether it's a good thing if everyone can do this is a debate for another day. 

The popular minute-by-minute Breathe app is now available as a new watch face. 

Got an Apple Watch already? Then check out the best Apple Watch accessories: Protect and personalise your watch