Ever since I've downloaded messenger, it keeps on draining my iphone battery. First I switched off background refresh, then I switched off notifications, making it nearly useless. Now, with everything turned off and it being basically unable to do anything unless I press the app, it still drains battery! Over the last 24 hours, it has 2hrs of background activity, and I haven't even used it! What else is there left to do than to remove it? In our region basically all text communication is done with facebook.