The way H9 Control used to work was it was killed whenever you switched out of the app. Now to make it work in the background, the H9 Control has to be active even if you are on other apps. By doing so it is possible to use 3rd party apps to send MIDI messages to H9 wirelessly through H9 Control. That's why the H9 Control is always active and consuming the battery. So now the app needs to be quit manually if you are not using it.