Apple is expected to launch its first foldable iPhone tomorrow, marking the biggest change in form factor for the device since it first launched in 2007. We have already got a good idea of what's coming, but the biggest mystery remains, what will the device be called?

iPhone Fold

The name iPhone Fold will get straight to the point, but Apple may want to give this device its own unique brand identity and therefore avoid the simple 'Fold' branding. Additionally, competitor Samsung already uses the Fold name.

iPhone Ultra

This is the top contender among many, with major publications such as 9to5Mac, commonly referring to the device as 'iPhone Ultra'. Some argue this fits Apple's existing branding, where Apple's top watch is the Apple Watch Ultra.

Apple's M-series chip also follows a similar pattern, with Pro, Max and Ultra chips. The iPhone lineup could become iPhone Pro, iPhone Pro Max and iPhone Ultra.

iPhone Duo

Apple could use a three letter word on its all new foldable device, that fits nicely with its other brand names Neo, Air, Pro and Max.

iPhone Duo could make sense if Apple wants to emphasise the foldable iPhone is like two iPhones joined together.

So far, leaks, renders and mockups of the device seem to resemble two iPhone Air models together.

iPhone Folio

Folio, meaning "a sheet of paper folded in half once to create two leaves or four pages, or a large book made from such sheets", describes exactly what the upcoming device is expected to be.

However, Apple currently uses the folio branding for iPad covers and previously sold leather iPhone folio cases. Apple is therefore unlikely to reuse the iPhone Folio name for its flagship iPhone device.

None of the above

Apple's marketing team are often very secretive, with rumoured names often being just guesses based on the device, rather than a substantial leak. In March, the MacBook Neo came as a shock to many, leaking just hours before it was announced.

On John Gruber's The Talk Show following WWDC23, the head of the Apple Vision Pro development project told Gruber that he did not know the device was going to be called Vision Pro until event day.

Apple could surprise us again tomorrow, or we might have the devices name sitting on this page right now.