The iPhone 4S, which went on sale just days before former Apple CEO Steve Jobs passed away, sports the same thin glass and stainless steel design of the iPhone 4. Apple has instead made its improvements under the hood, with the iPhone now powered by the same dual-core A5 processor as its iPad 2 tablet. According to Apple, this delivers twice the processing power and up to seven times faster graphics than the chip used in the iPhone 4.
The smartphone features a dual-antenna that intelligently switches between two antennae to send and receive data. Apple hopes this will address the call-dropping issue that plagued the iPhone 4, later rectified by fitting a bumper to the handset.
The refreshed handset features improved voice control in the form of Siri - "an intelligent assistant that helps you get things done just by asking", according to Apple. Siri provides relevant answers to questions such as 'will I need an umbrella this weekend?', utilizing the phone's hardware and some apps. The camera's megapixel count is now up to 8Mp, while low-light photography benefits from its f2.4 aperture. It also offers an onscreen grid to aid composition, image stabilization, real-time noise reduction and the ability to capture full-HD video.
Importantly, the battery has been upgraded too; Apple claims the iPhone 4S can now endure 8 hours of talk time.
Apple iOS 5
The handset runs iOS 5, the latest version of Apple's mobile platform. iOS 5 has 200 new features, including a redesigned Notification Centre and iMessage - a free service for sending messages, photos, video and contact information to other users of the app over Wi-Fi.
A Photos app lets you crop, rotate, enhance and remove red-eye from snaps, as well as organize photos into albums. One-click uploads to Twitter and iMessage are useful for sharing images.
Any device running iOS 5 can also access iCloud, Apple's online storage service. Music purchased from iTunes, photos, files and contacts can be held in a free account with 5GB of online space, from which they can be streamed to compatible devices. When the content changes on one device, all others are automatically updated, too.
iPhone 4S, plus iOS 5, plus iCloud, is a breakthrough combination that makes the iPhone 4S the best iPhone ever," said Philip Schiller, Apple's senior vice-president of worldwide product marketing.
While our competitors try to imitate the iPhone with a checklist of features, only the iPhone can deliver these breakthrough innovations that work seamlessly together.
The iPhone 4S is available in black or white, with 16, 32 or 64GB of storage. A SIM-free version can be bought direct from Apple, costing £499, £599 and £699 respectively. The UK's major mobile networks are also offering the iPhone 4S on a contract basis, with prices starting from £20 per month.
Within the first three days of availability, Apple said it had sold more than four million iPhone 4S handsets -that's more than double what it achieved with the iPhone 4, which sold 1.7 million in the same period following its launch.