IOS 13.4.1 and battery drain
Immediately after updating to iOS 13.4.1 my battery (97% health) began to drain from Mail-Background Activity. I set the Background App Refresh to OFF, Fetch for all mail and calendars is set to Manual. I did a system reboot. I have turned off all automatic updates, etc. I fully charged the battery, turned off the screen and let it set unused. In 9 1/2 hours the battery drained 39%. Is there some work-around for this problem? I have run out of things to turn off.
iPhone 8 Plus, 13