Today, in the latest version of MIUI, dual clock display function has been added to MIUI 10. The function is very practical for users who travel across time zones. One can not only see the local time but also simultaneously shows the timezone of the region where you are via GPS. Unlike dual clock display in other Android UIs, one doesn’t have to switch areas, add or subtract.
For the user who is using the latest MIUI 10 version, go to:
Settings >> date and time >> open in dual clock.
The upcoming MIUI 11 which is releasing before November, debuting in Xiaomi Mi MIX 4, will also feature the Dual Clock Display. According to the official information, MIUI 11 is positioned as a “new and unique OS”. In addition, MIUI advertising issues will also be resolved on MIUI 11.
Source (in Chinese)