Mi Band 2
It might be happen due to faulty battery which needs a replacement or it maybe due to improper way of charging Mi Band 2.
1st time, wear your Mi Band 2 Throbbing side(like below photo) then scan your Heartbeat Rate. After this activity, it'll work properly with normal wearing style.
Change language from mobile settings >> Additional Settings >> Language and Input >> Select your language. Mi Fit app shows language as per default phone's language.
1st, Unpair your Mi Band 02 from previous Mi Account in Mi Fit App then try to connect that Mi Band 2 to other mobile.
Open Mi Fit App >> Play >> Mi Band Alerts >>Manage Apps & Choose apps as you want.
Mi Band 2 is shows only some of apps icons (WhatsApp, QQ, Facebook, Twitter, Snapchat etc.). More icons will be introduced by developers perhaps in the upcoming update.
Connect your Mi Band 2 to your Mobile and Mi FIt app then go to Mi Fit App >> Profile >> Mi Band 2 >> Time Format and choose second option.
Open Mi Fit App >> Profile >> Mi Band 2 >> UNPAIR. It'll be unpaired from your mobile.
Open Mi Fit App >> Play >> Incoming call >> Off the option "Don't notify about unknown numbers".
More features will be added in future and this will be added through firmware updates which will be released by Developers when it is ready.
Open Mi Fit App >> Profile >> Settings >> Check For Update >> Update.
No, currently you are not able to do it. Feature might be available in future.
It might be happen due to positioning of the person while sleeping, the sensitivity of the Mi Band 2 sensor differ or it might be due to software issue.
Currently this feature is not available. Might be available in feature.
There's no way to downgrade the firmware of Mi Band 2 at this moment. Option might be available in future.