iPhone 5SE: Everything we know so far about Apple's small new handset

The technology rumour mills are getting awfully excited about the alleged development of a new, smaller iPhone. We don't mean thinner, because the iPhone somehow gets thinner every year, but a smaller screen.

That's right, despite Apple upgrading the iPhone from 3.5in to 4in in 2012, then to 4.7in and 5.5in in 2014, there is a mounting pile of evidence to suggest the next iPhone will drop back down to 4in.

It was first rumoured to be called the iPhone 6c, a natural successor to the unloved iPhone 5C everyone has forgotten about – remember, that one Jony Ive called "unapologetically plastic". Anyway, it now seems everyone is calling this new iPhone the 5SE, just to be really confusing.

Whatever it's called, we think a smaller iPhone with the design and performance of the iPhone 6 or 6S would be a great idea. We've always admired Sony for its Xperia Z Compact range, and this Apple alternative would breathe new life into a market that demands big performance in a pocket-friendly phone that can be used in one hand.

What have we heard so far?

The next Apple handset, currently dubbed the iPhone 5SE, will be revealed in March and it will have a 4in screen. The announcement is expected to happen soon after Mobile World Congress, which takes place in late February and is where the biggest Android phones of the year –including the Samsung Galaxy S7 – will be announced.

If Apple sticks to its usual lead time, we can expect the iPhone 5SE to go on sale a few weeks later, in April. This launch is unlikely to affect the release cycle of the rest of the iPhone line up, so the iPhone 7 and iPhone 7 Plus will still arrive in September, a year after the 6S.

The iPhone 5SE will have the same processor as the iPhone 6S

We wouldn't have put much money on this claim, but it comes from Mark Gurman of 9to5Mac, who is very reliable when it comes to iPhone and Apple rumours. He originally heard the new model would use the A8 processor from the iPhone 6, along with its M8 coprocessor, which analyses the handset's movement.

But now Gurman's sources claim multiple versions of the new iPhone are being used on the Apple campus in California, and the one with the A9 and M9 processors of the iPhone 6S is what will likely enter production. This would keep the new phone just one generation behind the iPhone 7 and its A10 processor when that arrives in the autumn.

The iPhone 5SE will replace the iPhone 6 and 6 Plus

Gurman claims: "We are told that the iPhone 5SE will likely replace the iPhone 6 and iPhone 6 Plus in the iPhone line up this fall when the iPhone 7 is introduced. This means that Apple's fall 2016 iPhone line up will likely be the iPhone 5SE, iPhone 6S and 6S Plus, and the future iPhone 7 and 7 Plus."

The iPhone 5SE will have a Siri that always listens

Another point about the upcoming iPhone is that it will have a Siri that always listens, even when the handset isn't plugged in and charging. Saying "hey, Siri" will instruct the phone to listen to its owner's voice.

The phone is also claimed to come in two storage sizes of 16GB and 64GB. It's a shame, as we have said numerous times, that Apple still offers any device with just 16GB of storage, but if this is meant to be seen as the "cheap" iPhone, we shouldn't be too surprised. If this is the case, we can at least hope the iPhone 7 will start at 32GB.

The iPhone 5Se could be just what Apple needs

Apple will report its first quarter financial results on 26 January and analysts are expecting to see the slowest growth iPhone history. This means Apple will have sold more iPhones than in the first quarter of 2015, but the difference will be the smallest yet, since it launched in 2007. A small, cheaper iPhone aiming the brand at a different area of the market could help to address this decline.

And, of course, the usual caveats apply. The leaks and rumours could turn out to be nonsense, or Apple might decide to cancel development of the iPhone 5SE before it is even announced. In two months, we should have an answer.