According to a recent industry report, Apple is planning an iPhone display that is very different from what is currently in fashion in China, namely the quad-curved trend from Xiaomi and others. It also has nothing in common with Samsung's Edge displays. However, there are reportedly problems with the implementation.
Why? What are we going to do with 1.5mm of extra screen space? Seems like a lot of effort.
I bet they need the technology for folding phones/tablets (instead of a crease, have two screens that but up against each other with no bezel) and this is how they get the volume in manufacturing to make those doable.