This could be the Sony Xperia XR66
Reportedly, the new device measures roughly 146.4 x 71.9 x 8.1 mm, thus being a tad larger than the Xperia X and Xperia X Performance, and almost certainly sporting a display of around 5 inches (possibly 1080p). We don't really know a lot about the phone's features, but we can spot a USB Type-C port at the bottom, a front-facing camera, and a rear camera with dual LED flash. A previous rumor had it that both the rear and front cameras would let users shoot 4K video - something that no other phone is currently offering.
When it comes to design, the alleged Xperia XR distances itself from the Xperia X family, as it has sharper corners, plus an interesting compartmented rear shell.