i have a 2 year old iPad Air2 that since the iOS 11.0 update is giving me an issue. The issue may not have anything to do with the update. At night I always plug the iPad into the charger and off to bed,but first I check to make sure the charge icon is being displayed. On two or three occasions lately in the morning I only have 30-40% usable charge. In other words sometime after I go to bed things aren’t charging as they should be.Any suggestions......the charger and cord seem in good shape....I’m hoping this isn’t a battery issue. Any help appreciated.