The rumour mill for the next iteration of the iPhone - currently believed to be the iPhone 5S - has finally begun to spin into action. Like “S” releases of the past - such as the iPhone 3GS and iPhone 4S - the iPhone 5S isn’t expected to bring any radical changes to Apple’s massively popular smartphone, but why mess with a winning formula? Today we’re going to serve up a rumour roundup that should bring you up to speed with all things iPhone 5S.

Photo credit: Martin uit Utrecht

Design

The iPhone 3GS didn’t offer up any physical differences from the iPhone 3G, nor did the iPhone 4S from the iPhone 4. All signs currently suggest that this will be the case for the iPhone 5S too, with the handset sticking with the slimmer and longer design of the iPhone 5. Apple’s flagship smartphone still holds up extremely well even in the face of rivals such as the HTC One and Samsung Galaxy S4, so we’re not too concerned about seeing the same design again.

Update: Japanese blog Macotakara believes that the iPhone 5S will be made available in a range of colours in additon to black and white. The site claims that the new colours could include green and gold. Unusual choices to be sure, but the addition of extra colours has been rumoured for the low-cost iPhone in the past. It makes sense that Apple would want to extend the same options to its flagship phone to spur further sales.

MacRumors has also recently received pictures of what's said to be a protoype for the iPhone 5S. Unsurprisingly, the handset carries an almost identical design to the iPhone 5.

That doesn't mean that Apple will stick with just black and white options, though. Apple columinist MG Siegler believes that the company will introduce a "gold" version of the iPhone 5S at its event next month. According to the writer, Apple will use a subtle champagne colour for the next version of the handset that will look different depending on lighting conditions. And that particular colour option might drum up some additional business, as gold is extremely popular in China.

That seems to be backed up by physical shells for the device too. The Verge and Buzzfeed have relayed pictures from Japanese site Ascii that compare a purported champagne gold iPhone 5S to the exisiting black and white iPhone 5s. The design appears to be identical - no surprise there - but the font used for the "iPhone" inscription seems to be thinner, lending itself well to the same font choices seen in iOS 7.

Screen

Apple decided to bump up the size of the iPhone’s display from 3.5-inches to 4-inches on the iPhone 5, bringing a slight increase in resolution and vertical height. It’s still one of the best displays on a mobile device, but we’re starting to see 1080p displays edge out Apple’s offering in terms of pixel density. If you’re expecting to see a similar resolution on the iPhone 5S, you’ll be in for disappointment: Apple isn’t expected to change anything in this department.

Update: Take this one as you will, but Chinese site EXPreview says that Apple will begin using IGZO displays for the iPhone 5S. Size and resolution will remain unchanged at 4-inches and 1136x640 respectively, but the use of IGZO will lead to more power efficient screens that can also achieve higher levels of brightness. IGZO sounds entirely logical, but we've also heard time and time again about how Apple will use IGZO technology in a future product without it ever actually happening.

OS and UI

Apple introduced iOS 7 to the world at WWDC 2013, with the mobile operating system seeing a dramatic visual overhaul. Gone are the heavy textures and visual metaphors, with lead designer Jony Ive instead opting for a much simpler, cleaner, and flatter interface.

Cupertino is already pushing out betas for iOS 7 to developers for use on currently available iOS hardware, with the final version expected in Autumn. Guess what else is rumoured for a release around that time? The iPhone 5S. It certaintly wouldn't be a stretch to say that we'll see the final version of iOS 7 preloaded on the iPhone 5S when the handset is made available later in the year.

Hardware

The physical design of the iPhone 5S isn’t expected to change, but the internals will most likely see a small bump that won’t be too far removed from “S” models of the past. The iPhone 5 is currently powered by an Apple A6 chip, and it’s not hard to see the company upgrading it to the A6X chip that currently powers the iPad 4.

EXPreview believes that Apple will increase the RAM in the iPhone 5S to 2GB. The site also claims that the company will use a quad-core graphics processor as opposed to the tri-core solution used in the current iPhone 5S. The Chinese site finishes by saying that the iPhone 5S could also include LTE Advanced capabilities.

The camera, meanwhile, is expected to see a an upgrade in megapixels. iMore once again reported on details pertaining to the next iPhone’s optics, saying in March that Apple is trying to “raise the bar”. More recently, Vietnamese leak site tinhte.vn heard from a source that the iPhone 5S will include a 12-megapixel camera, with a particular emphasis being placed on improved low light photos. It’s not hard to see why Apple would want to pursue that particular avenue: smartphones have been notorious poor performers in dimly lit conditions. Handsets like the Nokia Lumia 920 and HTC One have also shown that good results can be achieved with the right mix of hardware and software, so Apple may just try and show everyone else how it's really done.

Update: Macotakara reports that the iPhone 5S will include a dual LED flash as well as a redesigned rear microphone. The site claims that the microphone will now be circular, and that it will retain its position between the camera and flash. Macrumors has also alluded to the dual LED flash, with pictures of a purported prototype iPhone 5S featuring a pill-shaped flash module with two distinct LEDs.

9to5Mac believes that Apple may also include 120fps slow-motion video recording. According to the site, references to iOS 7 code point towards the "killer" new feature for the iPhone 5S, which may help to set it apart from the current iPhone 5. It's not clear what resolution 120fps recordings will be captured in, but the result will be slow-motion videos that could lead to interesting results. Apple has also apparently opened up 60fps video recording to developers in iOS 7 already, lending credence to the idea of even higher frame rate support in the future.

In terms of storage, Apple will most likely stick to the 16, 32, and 64GB capacities that it has provided with previous iPhones. The company could produce a wildcard and introduce a new 128GB model - an update to the iPad 4 added that option not too long ago - but it’s highly unlikely. The usage models between phones and tablets are vastly different, and it’s hard to see why even the most enthusiastic users would need 128GB of storage on a phone.

Finally, Apple isn’t expected to change anything with regards to connectivity or battery life. We may see the iPhone 5S supporting pentaband 3G bands thanks to recently added support for T-Mobile in the United States, or maybe even one single model for the multitude of LTE bands that are used across the world. The more likely scenario, however, is for Apple to keep offering multiple SKUs while waiting for modems to mature.

It doesn’t look like Apple will increase battery capacity in any way given that the design of the next iPhone is expected to be the same as the iPhone 5. That’s a shame considering that the battery life on the iPhone sometimes leaves much to be desired, but we may have to wait for the 2014 iPhone before seeing any progress on that front.

Still, the iPhone 5S may add a new hardware feature - a biometric fingerprint scanner. References to the new technology were recently discovered in iOS 7 beta 4, suggesting that the scanner will be embedded directly into the home button. 9to5Mac also hears from a source that the user interface for the fingerprint scanner has already been finished, which will allow users to unlock the handset by allowing the sensor to read their fingerprint.

It's not the first time we've seen mention of fingerprint scanners and Apple together either. The Next Web speculated last year that Apple acquired security company AuthenTec for its fingerprint scanning technology, possibly for a quick turnaround and inclusion in a future Apple product. The latest refernces in iOS 7, then, could mean that Apple has followed through on the implementation of the technology in the iPhone 5S.

Release Date and Pricing

The Wall Street Journal recently reported that Apple is set to begin production of the iPhone 5S over the summer, with the company aiming to announce the smartphone sometime in July. After that, we may see a release sometime in August. As for pricing, there isn’t anything to suggest that the next iPhone will be any more or less expensive than the iPhone 5. You can expect to see roughly the same price for both unlocked models and handsets on contract when the phone is eventually released.