Apple's iPhone 5S WILL have a fingerprint scanner that could stop other people accessing the phone Fourth beta release of Apple's iOS7 software features a Biometric Kit folder Code suggests fingerprint scanner will be added to the Home button Confirms rumours Apple is looking at installing the security feature Feature believed to have caused production issues and could delay release The strongest indication yet that Apple's new iPhone 5S will have a fingerprint scanner has been discovered by an app developer. A string of code discovered in the latest beta release of Apple's iOS 7 software implies that either the iPhone 5S or iPhone 6 could come with a fingerprint scanner. The code describes a user touching the Home button with their thumb. A fingerprint then appears on the screen, that changes colour - presumably to signify a match - and the 'recognition is complete'. A folder called Biometric Kit was also found. A string of developer code discovered in the fourth beta release of Apple's iOS 7 software, pictured, gives the strongest indication to date that either the iPhone 5S or the iPhone 6 could have a fingerprint scanner A folder called Biometric Kit, pictured, was also found and the feature could be for security reasons to unlock the phone, or to authorise payments in the App Store and prevent people from stealing your phone, reading your messages or obtaining personal data Rumours about a fingerprint scanner emerged before the iPhone 5 was released in September last year. Apple had purchased security company AuthenTec, which analysts claimed was because it wanted the firm's expertise in biometric technologies. The iPhone 5 did not include the technology, though, and this lead people to speculate that the next model - dubbed iPhone 5S - or later versions, such as iPhone 6, would include the feature. In April this year, rumours surfaced that the next iPhone model could be delayed because of this technology. A supply chain source in Taiwan told Reuters Apple was trying to find a coating material that did not interfere with the fingerprint sensor, and this may be causing production problems. Earlier this month a Chinese source claimed the date could even be pushed back to October. The feature could be for security reasons to unlock the phone, or to authorise payments in the App Store and prevent people from stealing your phone, reading your messages or obtaining personal data. The screenshots were tweeted by developer Hamza Sood. Rumours about a fingerprint scanner being introduced to an upcoming Apple handset first emerged before the iPhone 5 was released in September last year. Apple had purchased security company AuthenTec, which analysts claimed was because Apple wanted the firm's expertise in NFC (near field communication) and biometric secutiry technologies. The iPhone 5 did not include the feature, though, and this led people to speculate that the next model - dubbed iPhone 5S - or later versions, such as iPhone 6, would include the feature. A supply chain source in Taiwan told Reuters that Apple was trying to find a coating material that did not interfere with the fingerprint sensor, and this may be causing production problems. Then in May, PayPal's chief information security officer Michael Barrett claimed fingerprint scanners could spell the end of modern-day passwords and the technology would become more popular once Apple introduces it to one of its products. The developer code suggests the fingerprint scanner could be built into the phone's Home button, pictured. A supply chain source in Taiwan told Reuters that Apple was trying to find a coating material that did not interfere with the fingerprint sensor, and this may be causing production problems Motorola already uses fingerprint sensors on its Atrix 4G model, released in in 2011 and this feature is used in place of a password or PIN lock. Some laptops, including the Lenovo ThinkPad T430 comes with a fingerprint reader built-in. Other handsets, including Samsung's Galaxy S3 and S4, that run Android additionally have the option of enabling Face Unlock - a feature that uses facial recognition to unlock the phone. An update to the feature recently added a 'Live' element that required a person to blink, to prove they were real and it wasn't a photo being held up to the camera. Motorola already uses fingerprint sensors on its Atrix 4G model, released in in 2011, pictured. The biometric scanner is shown on the top of the rear of the phone. This feature is used in place of a password or PIN lock Various rumours have suggested that the new iPhone will be released on 6 September, 10 September and even October. The name has not been confirmed, but it has been dubbed the iPhone 5S following suit with Apple's iPhone 4 and iPhone 4S release schedule. Other features expected in the next Apple model include a faster A7 processor, improved Siri voice recognition, including Siri in the Car, as well as an improved camera. A larger iPhone 6 is then expected in 2014, and Apple is also rumoured to be working on a budget model. This cheaper handset is expected to come in different colours and be made of plastic. It could cost as little as £63. YouTube user DetroitBORG recently posted video that appears to be the first hands-on look at this rumoured plastic casing. In the video, DetroitBORG compares the current iPhone case with the plastic model. He claims it is large enough to fit on a phone with a 4-inch display. VIDEO: A sneak peek at what is thought to be the new budget plastic Apple iPhone