Code put together to read the temperature and humidity from a Xiaomie BLE sensor (MJ_HT_V1). Works with the default Arduino BLE library on Arduino version 1.9.
Shows results on the display of an M5STACK and in the serial terminal. Remaining issues are receiving of mixed BLE packets and sometimes the thing is unstable after changing a few lines of code. Sometimes also only works at start-up and than stops.