Rumors persist that Apple is currently working on at least two new foldable iPhones and that their chassis are undergoing testing at the Foxconn facility in Shenzhen, and have passed durability testing.
One prototype is said to be in a clamshell form factor, à la the Samsung Galaxy Flip or the Motorola Razor. When the unit is opened it would be one large continuous screen and when the user goes to close it the top folds down over the bottom.
The second prototype will reportedly have dual screens connected by a hinge similar to what's on the Microsoft Surface Duo. A new patent was filed titled "Folding Electronic Devices With Geared Hinges" which explains the need to give users larger screen real estate without making the new device too bulky.
As with all patent filings from Apple, you have to take it with a grain of salt as to what the final product will look like, what tech they'll be using, and when it may be available which according to rumors may be as far away as 2023.
All the patent filings confirm is that Apple is now taking a serious look at creating and building a foldable iPhone soon. What form factor, specs, or even what the actual device will truly be, if it's actually going to be an iPhone, or maybe even a new iPad of some sort, we'll just have to wait and see.