New iPhone products are due to launch at 5pm 10 September

What can we really expect from this afternoon's iPhone launch?

So, the new iPhone range is nearly upon us. With the rumour mill spinning on overdrive users we’ve been led to expect two new models of iPhone (one “budget” version and one second generation improvement on the iPhone 5), while Apple aficionados the world over have also been guaranteed a brand new operating system.

But what are the four big revelations we can really expect from Apple’s campus in Cupertino, California this afternoon?  And what do those mysterious single letter suffixes (“S” and “C”) really mean?

1. Fingerprint security

Siri was the standout feature of the iPhone 4S, but what will that mysterious “S” – which Apple declines to clearly define – stand for this year? “Security” seems to be the buzzword doing the rounds this year, with all signs pointing to a fingerprint sensor as the standout feature of the 5S.

Images of the new model, leaked by Chinese website C Technology, appear to show a silver ring encircling the home button – an added feature which many have taken as evidence of Apple’s effort to impose fingerprint security on the new phone. Tech speculators say this could mean a feature for unlocking the homescreen or for confirming identity for payment in the App store and other outlets.

If the rumours are true, iPhone users will have to hope Apple has got the technology right. In 2011 Motorola tried the same thing but was embarrassed when many customers reported that the feature simply didn’t recognise their fingerprints.

2. Sparkling colour

Apple is thought to be releasing not one but two new models of the iPhone this year, with the iPhone 5C being touted even before its release as “the iPhone Cheap” – a plastic, reduced cost version of the iPhone aimed at developing markets. Others say that appended “C” stands not for “cheap” but for “colour”, with the budget model thought to be offering handsets in a number of bright, lively tones.

Australian blogger Sonny Dickson also published a number of pictures that puport to show the back shell of the iPhone 5S. If the pictures are genuine then 5S users can hope to expect coloured second generation phones in both “champagne gold” and “silver graphite” hues, in addition to the regular black and white colour schemes already offered.

3. Improved processor and camera

Boring but of practical importance, the iPhone 5S is also thought to be equipped with hardware improvements making it faster and more efficient and aiding the length of battery life.

An improved camera is also expected, with a better flash for taking photos in low light conditions.

4. Software

It’s not only new models but also a new operating system – the iOS7 – that is expected to launch today. And Apple have not been afraid to boast about their new software: CEO Tim Cook describes the iOS7 as “the biggest change to iOS since the iPhone”.

What does that actually mean? In all probability users can expect an overhauled interface with flatter, more colourful icons and an easier-to-use, more intuitive control centre – reachable from anywhere on the phone.

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