Use APKPure App
Get OpenBand old version APK for Android
Open Source app for your MiBand!
Written for fun, basically for personal purposes.
PLEASE NOTE: you have to disconnect your MiBand from the official app to make this work.
Released under the tems of GPL v3 license. [1]
[1] http://www.ugopiemontese.eu/portfolio-item/openband-android-app/