The Stable update V184.108.40.206.SKMCNXM has been officially released for MIX 4 (codename is odin). Before updating, please make sure you have downloaded the exact ROM matching your Xiaomi phone/tablet. In Fastboot mode, you can check model code by typing
fastboot getvar product in cmd/shell.
The firmware files posted here are all official Xiaomi ROM, xiaomiROM.com do not own and never modified those firmwares，you will always download the file from Xiaomi server.
You may interest in those contents: MIX 4 ROM Topics Xiaomi Devices Index
Download Mi mix 4 (odin) China MIUI 13 V220.127.116.11.SKMCNXM Recovery ROM with Android 12.0. Firmware size is 5.2 GB.
Download Mi mix 4 (odin) China MIUI 13 V18.104.22.168.SKMCNXM Fastboot ROM with Android 12.0. Firmware size is 7.5 GB.