But, for those who really want English, and are willing to lose some of the benefits of Xiaomi's applications (remote downloads, Android app, etc...), I think you should flash OpenWRT: http://wiki.openwrt.org/toh/xiaomi/mini
Xiaomi took a step back in supporting English, and took off the English language option on their Mi Wifi Android application.
Adding to this, the router's UI was never updated to English, as promised by Hugo Barra himself on his video.
This application is particularly important to:
- Connect your router to your Mi Account: to get the most out of your router, or to simply have access to the SSH kit in order to flash OpenWRT; and
- Access to more features and options - which are not available through the Web UI - like: install plug-ins (like Samba, DLNA, amoung others), defining a Wifi off period or setup a scheduled reboot everyday.
You can still download the application from the Play Store here with English support, but, usually, it is an older and Stable version that can be erased in the future by Xiaomi.
The English Web-UI ROM mentioned in the above comments is an altered ROM, made by a Chinese retailer, which is not recommended to use, due to privacy and stability issues, as it is an older version highly adulterer by a stranger.
I do not recommend it!
For future use, I leave here a link to download the latest version of the application with English support.
You can download it here.
It is the Developer version 2.3.15.