How to Stop Your iPhone Battery From Draining Fast After an iOS Update
Open Settings > Battery > Battery Health & Charging and turn off Optimized Battery Charging for 24 hours, then in Battery usage tap the top 2 or 3 hungriest apps and disable Background App Refresh only for those specific apps instead of all apps. This targeted reset plus a day of normal use lets iOS finish its reindexing, calms the battery analytics, and usually restores normal battery life without gutting your phone’s features.
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