The very latest rumor on Apple's first foldable iPhone is that it will release sometime in 2023, with an OLED display ranging between 7.3-inch to 7.6-inch and would support the Apple Pencil, too.

The news is coming from Chinese investment research firm EqualOcean which predicted the foldable iPhone will launch in 2023. The report reads: "Omdia, a global communications and digital media research organization, predicts that Apple may launch a 7.3-7.6-inch foldable OLED smartphone in 2023 and add an activity pen to its foldable iPhone".
We heard back in October 2020 that the foldable iPhone could even have self-healing display technology, which was teased in a new patent at the time. The foldable display would be protected against small scratches from being placed in and out of your pocket or bag, or onto the table for example.

Apple using a larger 7.3-inch to 7.6-inch OLED display would put the purported foldable iPhone at the display size of the iPad mini, which packs a 7.9-inch panel. Samsung is already up there with its Galaxy Fold and new Galaxy Z Fold 2 foldable smartphones.
We should hopefully hear more concrete info on the foldable iPhone later this year.