Apple has unveiled the iPad Air, a top-of-the-range tablet that is 20% thinner than the previous version.

The 9.7in computer is 0.3in thick and weighs 1lb, which Apple claims is the lightest full-sized tablet on the market.

iPad Air is powered by the same A7 chip found in Apple’s iPhone 5S.

The launch comes at a time when some analysts have suggested that Google’s Android is about to overtake Apple’s iOS as the bestselling tablet platform.

Apple also announced a new version of its iPad Mini.

Apple has unveiled the iPad Air that is 20 percent thinner than the previous version

iPad Mini’s 7.9in screen has been upgraded to feature 2048 by 1536 pixels – the same as the larger model. It is being branded as “retina” to highlight the increased resolution.

Apple also announced that the latest version of its Mac operating system, Mavericks, would be offered at no cost to owners of computers already running any version of OS X released since 2009. It is the first time the company has not charged for a major Mac OS upgrade.

By contrast the full version of Windows 8.1 is sold for about $150, although it is free to existing Windows 8 users.

Linux-based Ubuntu has always been offered without charge. Chromebook computers also get free upgrades for Google’s PC operating system.

New laptops, productivity and leisure apps were also unveiled. However, Apple did not show off a new TV set-top box as some had speculated.

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