Here is the Global update for�MIUI 7 Based on Android 6.0 Marshmallow for Mi3.
How to Update your Xiaomi Mi3 to MIUI 7 Based on Android 6.0 Marshmallow
Install MIUI 5.12.17 first to merge your system partitions (no more dual system support)
After reboot install current 6.1.21 version - let it boot and update all apps, then reboot again.
Wipe data not needed but recommended.
Don't forget to share this among your Mi3 friends. Let them also taste the Android 6 MIUI
CHANGELOG
[Lockscreen, Status Bar, Notification Bar]
New - New version of daily lockscreen. Support viewing, sharing, and apply wallpapers on lockscreen (01-19)
[Weather]
Fix - Weather FCed after closing its settings menu (01-19)
[Permissions Manager]
New - Manage permission to create home screen shortcut. Restrict all apps' access to a specific permission in one press (01-20)
Fixed Recommended apps in folders
Added GMS icon
Added Sunrise/Sunset in the weather app
