A Xiaomi executive may have just revealed when MIUI 13 will be released. It's possible the Android skin could make an appearance in August, right on time to be found running on the long-awaited Xiaomi Mi Mix 4. Supposed battery and charging specifications for the Mi Mix 4 have also found their way online.
https://www.notebookcheck.net/MIUI-13-possibly-coming-in-August-right-on-time-for-a-rumored-Xiaomi-Mi-Mix-4-release.547479.0.html