According to the renowned Weibo tipster, Digital Chat Station, the Xiaomi 12 Ultra won’t be offering any upgrade over its predecessor when it comes to sensors. The 50MP+48MP+48MP configuration will be retained in the upcoming flagship.
The machine-translated text does mention something about “super-telephoto periscope” but it’s unclear if that refers to the same 5x lens as on the Mi 11 Ultra or a new, longer-reaching, one.
The report from Digital Chat Station seems to be in line with previous rumors that the camera modules will be the same even if the camera island will be revamped.
Source (in Chinese)