(Telecompaper) Apple has released its iOS 8 SDK, its largest developer release to date with more than 4,000 new APIs. iOS 8 allows developers to further customise the user experience with extensibility features like Notification Centre widgets and third-party keyboards, and introduces frameworks such as HealthKit and HomeKit. iOS 8 also includes Metal, a new graphics technology that enhances the performance of the A7 chip and Swift, a new programming language. The iOS 8 beta software and SDK are immediately available for iOS Developer Programme members at developer.apple.com. In the fall, iOS 8 will be available as a free software update for iPhone 4s, iPhone 5, iPhone 5c, iPhone 5s, iPod touch 5th generation, iPad 2, iPad with Retina display, iPad Air, iPad mini and iPad mini with Retina display.