Hello Xiaomi Mi MIX fans,
Been wondering? How are you going to update your ROM, like updating or downgrading within China Stable ROM or migrating to the featured friendly China Development ROM or vice-versa. Let's go about it!

Updating via Recovery Method:
Download the latest MIUI ROM file Recovery ROM on your PC/Computer and copy it to your "Download" folder on your device, as shown on the image below:

Next, goto to Updater App, click on the "3 dots" (top right-hand coner) and choose "Choose update package", goto "Download" folder and Choose files, and choose the Recovery ROM zip file you just copied from the PC/Computer and select and tap "OK". It wil then verify the the package "Getting info" and reboot automatically and flash the Recovery ROM accordingly, as shown below:

Now the China Stable MIUI 8 v8.0.11.0 MAHCNDI has been flashed to China Development Build MIUI 8.6.12.7 successfully. Enjoy!

Rolling-back or downgrading on Recovery Method:
Note: This works for.the same ROM variant and not between different ROM variant eg. China Dev to China Stable or vice-versa.

Download the MIUI Recovery ROM file from Mi MIX - Previous ROM Downloads onto your PC/Computer and copy it to your "Download" folder on your device, as shown on the image below:

Next, goto to Updater App, click on the "3 dots" (top right-hand coner) and choose "Choose update package", goto "Download" folder and Choose files, and choose the Recovery ROM zip file you just copied from the PC/Computer and select and tap "OK". It wil then verify the the package "Getting info" and reboot automatically and flash the Recovery ROM accordingly, as shown below:

At this stage, you just need for it to reboot, and you successfully, downgraded from China Stable v8.0.11.0 to China Stable v8.0.10.0.

Can't verify update:
This error will show if you are downgrading on China Dev to China Stable, as shown below: