Xiaomi's next Mi 9 and Mi Mix 4 will also use three rear cameras, according to a survey note released by Hong Kong's GF Values. In the Xiaomi market report, the analyst mentioned the first smartphone of the company Mi 9 with three rear cameras.
Additionally, Mi Mix 4 is apparently a Periscope lens, allowing more optical zooming, while the chassis does not require more space (at least the thickness axis).
Mi 9 and Mi Mix 4, Qualcomm Snapdragon 855 expects, of course, it is impossible that these two be Xiaomi flagship in 2019. The mixer could be a folding 4 screen, but it's probably not yet decided. While my 5G version of Mix 3 will be a 5G Xiaomi phone, My 9 5G may also be an iteration.
Source (in Chinese) | Via