With its bigger screen, better wireless, a faster processor and higher-resolution camera, we take a look at the important changes to the iPhone 5. See also: Apple iPhone 5 hands-on review
iPhone 5: the 4-inch screen
Although it retains the familiar look and feel of both the iPhone 4 and 4S, the iPhone 5 now has a 4-inch, 16:9 screen with a resolution of 1136x640 pixels. This means the screen is 176 pixels taller than the 4 and 4S, allowing an extra row of icons on the iOS Home Screen.
The change in height, not width, Apple says, is because it fits your hand better. It's clear, though, that there's pressure from other smartphone manufacturers to increase the screen size. Indeed, four inches is small by today's standards: Nokia's forthcoming Lumia 920 will have a 4.5in screen, and the Galaxy S3 feels gigantic with its 4.8in display.
See also: iPhone 5 launch video
The iPhone 5's display is more advanced than simply extra pixels. It has a built-in digitiser, removing a layer and enabling Apple to make the iPhone 5 thinner. Previously, the touch-sensitive layer was separate and laminated to the screen in the iPhone 4 and 4S.
Apple says this means the iPhone 5's display is clearer than ever (it still has the same 326 pixels-per-inch density as the 4 and 4S), and has 44% more saturated colours. There's no change to brightness and contrast though, with a claimed 500cd/m2 maximum brightness and 800:1 contrast.
All of Apple's apps will be updated to use the extra pixels, and we expect most developers to release updates for their third-party apps shortly after the iPhone 5 goes on sale on September 21st.
iPhone 5: dimensions and construction
The iPhone 5 measures 124 x 59 x 7.6mm, and weighs 112g. This compares to the iPhone 4S's dimensions of 115 x 59 x 9.3mm and 140g weight.
It's available in black and white versions, but the back design has changed. There's now a contrasting matt and gloss finish, since the panel is now primarily made from series 6000 anodised aluminium with glass inserts at the top and bottom. The black version of the phone has a darker metal band than the white version, which sticks with the same silver colour as before.
iPhone 5: iOS 6
The iPhone 5 will ship with the latest version of Apple's mobile operating system. iOS 6 includes plenty of new features, which you can read about in our separate iOS 6: what you need to know article. It includes a more capable Siri voice assistant, new Apple-designed Maps, a new Passbook app for tickets and coupons, integration with Facebook, shared Photo Streams, improved email, phone and internet browsing features.
iPhone 5: wireless
One of the other big updates is that the iPhone 5 will support 4G in the UK. You'll likely pay a premium for a contract which gives you mobile data via 4G, though, and carriers such as EE and 3 are yet to announce pricing. Due to its design, it won't support O2 or Vodafone's 4G networks.
Download speeds over 4G are up to five times faster than 3G, which the iPhone 5 also supports. Depending on who you buy an iPhone 5 from, you may or may not get the option of 4G data, with many networks only able to provide 3G, at least for now.
The network provider will also have to supply a new nano SIM, which is smaller than the micro SIM used by the iPhone 4 and 4S.
Wi-Fi has been improved in the iPhone 5, with a dual-band 802.11n radio. This means it can connect on either 2.4GHz or 5GHz with compatible hotspots and wireless routers. Using 5GHz is both faster and more reliable than 2.4GHz, primarily because the 5GHz band isn't yet widely used so fewer devices are competing for the bandwidth.
There's also the latest version of Bluetooth, 4.0, which is the same as the iPhone 4S.
Interestingly, Apple has decided not to include NFC in the iPhone 5. NFC is used in the Samsung Galaxy S3 and Nokia Lumia 920 to pay for purchases and share content between devices.
iPhone 5: storage capacity
There's a choice of 16GB, 32GB and 64GB models, meaning that the maximum capacity hasn't improved on the iPhone 4S. As before, there's no way to increase storage through the use of a memory card.
Next page: performance, cameras, ports and price