With upgrade to latest version of iOS 11 ie iOS 11.3.1 iPhone users are facing quick battery drain issue in iPhone SE/6s/7. Even the latest flagship iPhone X from Apple is reported with quick battery drain in iOS 11.3. The battery drain with new iOS is so servre that even for use of 5 minutes has resulted in 15% drop in battery of iPhone. Battery is draining ridiculously fast even when kept in asleep at night and no use of the cellphone.
When analysed the battery stats the user finds that its showing App store Audio which is causing huge battery drain. The app store uses "audio" and drains anywhere from 30-90% of the battery really fast. Even the low power mode does not seem to help much to stop fast battery drain on iPhone.
Fix :1 Turn of automatic downloads
Try to turn off the automatic downloads (settings->itunes & app store) for music, apps, books & audiobooks, updates. Any of hanged appstore updare can cause battery drain in iPhone
Fix 2 : Reset your apple account
Log out from your apple account, and then restart your phone or ipad. Now you can re-login on your apple account again.
Fix 3: Toggle Bluetooth Setting on iPhone
The issue is majorly reported by users using Apple watch and once you turn off the Bluetooth to off there are chances that it should stop battery drain in your iPhone