Hi there! I have the same problems of battery drain on my mi2s with both developer and stable versions.
I bought a new genuine orange battery (production date 2016) this summer on AliExpress, but it drops from 30-40% to 0%. I tried to calibrate it without success
, so I have put the old one again that is quite good yet. In addition, I bought also a charging port replacement, so I can try it about the fix mentioned above!!
Anyway my concerns now are the WiFi and network problems on both 8.2.1.0 and the 8.1.2.0 stable (I downgrade with the hope to fix them but still present). Mobile Network is really slow, while WiFi isn't stable at all because the connection is always present but frequently it doesn't exchange data, so I have to switch off and power on it again. Has someone these problems?
Grazie