The iPhone 6 is the most eagerly awaiting smartphone of the year and many are expecting the next generation Apple device to be unveiled in September. The smartphone will come with upgraded features and is a dead cert to be a bestseller with legions of Apple fans waiting to get their hands on the phone.

First of all the next generation may not be called the iPhone 6 at all – but could in fact be the iPhone 5S, or even the iPhone 5C. As usual Apple are not giving anything away and fans will have to wait until the big unveiling to find out exactly what will be Apple's newest smartphone.

Whatever it is called, many analysts are predicting that Apple will seriously try to up its game and increase the features and specs on the device following huge competition from other devices such as the Samsung Galaxy S4, the Sony Xperia Z and the HTC One.

Given Apple's history of announcing a "half-step" model before a completely new numbered model, many are expecting the new iPhone to be called the 5S or 5C. However, some are also expecting there to be an iPhone 6 in addition to one of those – although the iPhone 6 could be due to come out a number of months after the 5S or 5C.

Others still believe that Apple will flood the market with a stream of new iPhones, and that all the devices will be unveiled – the iPhone 6, 5S and 5C altogether.

The iPhone 6 will likely run the iOS 7 – with the new operating system being announced at WWDC 2013. The iOS 7 should be landing in September or October, in line with previous releases.

The iPhone 6 will also likely have an upgraded processor, with a quad-core A7 providing more power, better efficiency which would give better battery life too.

Some rumors have suggested the new device will also have a 13-megapixel sensor which should take up less room while still offering a top quality image for photos.

Eye-tracking and fingerprint sensors have also been touted, although it is not abundantly clear how certain those features are for the new device.

Others rumors surround the new iPhone having better 4G LTE, and wi-fi with an ultra-fast 802.11ac. Still other rumors suggest wireless charging will be unveiled by Apple, which would be a big step up, and a feature that is sure to go down well with smartphone fans.