This is an iteration of the MIX 4 MIUI 12.5 ROMs. The first MIUI 12.5 firmware or update for MIX 4 has already been released on 2021-07-28 by Xiaomi. You can now download the stable, weekly, or beta MIUI 12.5 ROM for your phone/tablet with device code odin. The last version of MIX 4 MIUI 12.5 ROM has been rolled out on 2021-12-09. It is recommended to update to the latest MIUI12.5 to experience the new features. If you want to upgrade or downgrade your MIUI version, you can find more details on the MIX 4 ROM section page.