At 2019 September, MIUI 11 has been announced and launched a month later. This allows the introduction of MIUI 12. As revealed through Chinese special social media (Weibo) a few days ago, Chinese smartphone vendor Xiaomi is certain to announce the presence of MIUI 12 as the successor of MIUI 11.
Unfortunately, Xiaomi has not provided any information about MIUI 12 yet. It only shows the logo will be used by MIUI 12.
Therefore, what kind of improvement will be carried by MIUI 12 is not confirmed just yet.
As a side note, some MIUI 11 versions are built based on Android 10 by adding a number of UI changes. In MIUI 11, the application icons are displayed more softly, including a new font named Milan Pro, and improved “always-on display” feature functionality.
Considering the schedule announced and launched MIUI 11 ago, MIUI 12 could also be introduced to follow the schedule of its predecessor. However, there is a possibility that information about MIUI 12 will appear in the weeks or months later.