A customer compares pictures taken with an Iphone 6 (R) and the new Iphone 7 (L) at Puerta del Sol Apple Store the day the company launches their Iphone 7 and 7 Plus on September 16, 2016 in Madrid, Spain / Gonzalo Arroyo Moreno/Getty Images

No hardware will be revealed, but the software that powers the extra-special phone will be shown off

Apple is about to host WWDC, its biggest developer event of the year. And it might also show off the future of your iPhone.

Though WWDC is mostly a software event, because it's a developer conference, it does sometimes use it to show off hardware. This year that's rumoured to be the premiere of its Siri speaker, alongside updated versions of the iPad and Mac.

But one thing will very much be lacking in that lineup: the iPhone. That always gets its own event now, and will come out in September.

Follow our WWDC liveblog here.

We might get a peek at it, though. Apple will reveal iOS 11 – the operating system that will power the iPhone 8, as well as probably the one currently in your pocket. And that might be a good way of guessing what's coming.

Here's what to look out for at today's keynote if you're interested in the future of the phone.

Augmented reality

One big focus for the next iPhone – perhaps the big focus – is augmented and virtual reality. The handset is rumoured to have a range of features that make that easier – depth-sensing cameras, for instance, which can allow the phone to project things onto the real world.

But all of the proper work for AR and VR are going to rely on software, and lots of it. If it's going to do anything interesting when it comes out then developers will have to get to work now, because it is a new and innovative area of work that developers aren't going to have a great deal of experience in. They need to be introduced to it now if Apple is going to have any interesting third-party ways to open up the features when it reveals them in September.

But, of course, it might choose not to have any interesting uses at launch. It didn't with the big camera technology that came in the iPhone 7 – the dual lens camera system that's only found in the Plus. Instead, it just integrated those depth sensing and zoom features into its own camera app, and didn't let anyone use it.

Apple has made some inroads with this so far – the AirPods are a very subtle computer, which allow you to talk to your iPhone by just tapping your ear. We're likely to see more of it over time.

Pro features

The next handset might be referred to as the iPhone "Pro", according to some leaks. And if it does, it's going to have a lot of work to do: the "pro" designation across Apple's lines usually refers to the fact that it can be used for business and is reliable.

What's more, whatever the iPhone is called, it is expected to be very expensive – far more expensive than any other iPhone ever made. As such, it will be expected to live up to that price – including features that can allow it to be justified as a proper computer, for instance.

So if the iPhone packs in some of those more advanced features – like proper ways of dealing with files, and dragging and dropping between apps – then we might also expect a bigger, better iPhone to go alongside them.

Will the iPhone get even bigger?

The iPhone has been growing at a fairly rapid clip: it began very small, then got longer with the iPhone 5, and then the iPhone 6 brought with it two sizes – one of which, the Plus, is positively huge compared to the original handset.

There have been rumours that Apple will be able to make the screen even bigger, while shrinking down the bezel that wraps around the side of the screen. If that happens, then it will become even harder to reach the edges of the display – and so Apple might provide some ways in the software to avoid having to reach all the way across.

How will it get bigger?

If that actually happens, then the screen might go where the forehead and chin sit at the top and bottom of the iPhone today. If it does, then some people have suggested that will be too long for a normal screen, and the top and bottom will function as some sort of extra display for showing status and other information.

If that does happen, then it will have to be built into the operating system. Apple will probably choose to unveil exactly how that will work alongside the phone – but there might be some clues in what gets shown off at WWDC.

A healthy focus?

Apple has been working hard on health, particularly in its Apple Watch. But much of the work of actually monitoring people's fitness can be done better on the iPhone, which has a bigger screen and more powerful guts for digesting the data.

So if there's a health focus in iOS 11, then that's likely to be carried through to the iPhone. Will Apple add better features for tracking your own eating and exercising, for instance? We'll probably be able to see depending on what the software can do.

Easter eggs

The best stuff is often hidden in the operating system, because Apple doesn't want to spoil it before it comes. But some of the rumoured features of the new iPhone – like wireless charging – will need significant software updates to work, and so it might be likely that they'll come out before the phone does.