The Xiaomi MIX Fold 2 will be released in August 2022. As a result, it is possible that it will be replaced by the MIX Fold 3 in Q3 2023. There is currently no information available on the Fold 3's additional specs.
Tipster just shed more light on the Xiaomi 13 Ultra's rear cameras. It is expected to include a quad-camera configuration with a 1-inch Sony IMX989 50-megapixel main camera. The primary snapper will almost certainly feature gimbal optimization, and all four snappers will almost certainly support PDAF autofocus.
Nothing more is known about the Xiaomi 13 Ultra's additional specs. However, it is quite likely that it will be equipped with the Snapdragon 8 Gen 2 processor, which is projected to power all 2023 Android flagship phones as well as the Xiaomi 13 Ultra.