Apple's next iPhone is arguably the most anticipated gadget unveiling of 2011 and it's taking place on Wednesday at 4am (AEDT) - Tuesday in the US.
And with any big Apple product announcement, the rumours have been flying for months - even former US Vice President and Apple board member Al Gore has fed some of the speculation.
Giga Netzwerk has created an iPhone 5 mock-up based on leaked hints so far. The prototype has a larger 4-inch screen.
Let's take a look at what's been reported so far, so we can see what pans out or what doesn't...
The standard right now for high-end smartphones (such as the Droid Bionic and Samsung Galaxy S II) is a dual-core processor, about 1 gigabyte of RAM, at least 16 gigabytes of storage memory and an 8-megapixel rear camera capable of shooting 1080p high-definition video and a better-than-VGA front facing camera.
The iPhone 4 currently runs on the Apple-designed and Samsung-built A4 single-core processor. The iPad 2 saw the debut of the dual-core Apple A5 chip, and the next iPhone is widely expected to gain the A5 chip, bringing it in line with its Android rivals. A boost in RAM would be needed to really capitalise on a faster dual-core processor, so these go hand in hand.
The iPhone 4's 5-megapixel rear camera is considered by many to be one of the most capable cameras available in a smartphone today, even at more than a year old. Nonetheless, a rumoured upgrade to an 8-megapixel rear camera is expected and anything less would be disappointing considering how widespread of a feature this has become in competing smartphones.
Up front, the iPhone 4 has a VGA-quality camera (as seen on Apple's iPad 2 and iPod Touch), and that is rumoured to be getting an upgrade too. An upgrade here would make sense, in part because Apple has already upgraded many of its laptops with high-definition cameras above their monitors.
The next iPhone is also rumoured to be offered in storage sizes of not only 16 gigabytes and 32 gigabytes as is offered now, but also with a 64-gigabyte option.
The size of the next iPhone's touch screen has been a topic of debate and contradicting speculation for months. Rumours have ranged from the next iPhone retaining the 3.5-inch display of the previous four generations and an increase to 4 inches (10.16 centimetres) or even 4.5 inches (11.43 centimetres).
The iPhone 4's 3.5-inch (8.89-centimetre) screen introduced the "retina display" with a resolution of 960-by-640-pixel and a crisp 326 dpi (dots, or pixels, per inch). The screen is so beloved by Apple iPhone owners that rumours have persisted since before the launch of the iPad 2 that the iPad would eventually see such a dense display.
Given how much iPhone users enjoy the iPhone 4's screen, this rumour may end up not seeing the light of day.
However, the fact that the next iPhone has taken more than a year to hit stores since the iPhone 4's launch has given rise to rumours that problems with producing a larger display are what have delayed the release of the next iPhone.
iPhone 4S or iPhone 5:
Simply put, if the next iPhone has a bigger screen, it needs a new body, a new form factor. If the screen stays the same, it could make use of the same form as the iPhone 4.
When Apple moved from its second-generation to its third-generation iPhone, the name changed from the iPhone 3G to the iPhone 3GS. The form factor remained the same, but the internals were upgraded, and the S was added to the name to indicate the bump in speed and improved software of iOS 4.
If Apple debuts a new design, the likely name will be the iPhone 5, if the Cupertino, California, tech giant follows its past naming pattern.
Among the rumoured design choices if Apple unveils a new look for the next iPhone is a "teardrop" shape that tapers from a thicker top to a narrower bottom, similar to the look of the MacBook Air in profile.
Supposed iPhone cases have been leaking from China for weeks and even reportedly showing up at US telco AT&T stores, leading some to believe that the teardrop look is coming. However, Apple pundit John Gruber weighed in with a smart argument that a teardrop design wouldn't make sense for an iPhone because it would lead to an unbalanced feel in the hand, especially when playing games horizontally. That runs contrary to Apple's industrial design themes and emphasis on ease of use.
One iPhone or two?:
With differing views on whether the next iPhone will receive a new body, some have taken to the rumour that Apple could release two phones, both an iPhone 5 (possibly with a larger screen) and an iPhone 4S.
One move that is likely (whether we see two new iPhones or one) would be for Apple to take the existing iPhone 4, drop its storage memory down to about 8-gigabytes and sell it at a low price. Apple made this move with the iPhone 3GS when the iPhone 4 was released, selling an 8-gigabyte version of that handset in the US for $US99 from AT&T.
This too has been rumoured, with varying and conflicting reports projecting just how it will all play out.
Siri and the Assistant:
Possibly the least reported of the rumours mentioned in this post is that the next iPhone could gain a groundbreaking new feature called "assistant" that would allow for deeper integrated speech controls.
But Assistant, as rumoured, wouldn't be just any speech input feature, it would actually allow iPhone users to speak a conversational style request into their device and Assistant would perform the requested action by identifying the necessary app and then using that app to get the appropriate data.
For example, a user in Sydney could say something like "I want to go to a soccer game on Saturday", and then the Assistant program would find out that both Sydney FC and Newcastle Jets play Saturday, then report back to the user where they play, against what teams and how much tickets would cost, with links to all the information needed to buy tickets and attend a game.
The news outlet that reported on what Siri could look like in the next iPhone the most has been the blog 9to5Mac, which has quoted Siri co-founder Norman Winarsky as saying that he doesn't know the particulars of what Apple is doing with Siri's technology, but "Make no mistake: Apple's 'mainstreaming' Artificial Intelligence in the form of a Virtual Personal Assistant is a groundbreaking event. I'd go so far as to say it is a World-Changing event."