MIUI 11 has not been around for long, but Xiaomi may have already ceased development for the OS. Set to be replaced by MIUI 12 later this year, a quickly deleted roadmap claims that Xiaomi will start issuing betas in late Q3 2020.
https://www.notebookcheck.net/Xiaomi-ends-MIUI-11-beta-development-as-MIUI-12-roadmap-appears-online.458917.0.html