iOS 13.3 improves battery life and performance on older iPhones
iOS 13.3 Battery Life - One Week Later : Follow Up Video - YouTube
MacRumors.com al Twitter: "iOS 13 Battery Drain: 15+ Tips to Make Your Battery Last Longer https://t.co/hPqo7eRQFE by @julipuli https://t.co/3hn5silTNI" / Twitter
iOS 13.3 issues: Parental controls, battery drain, and more - Mobile Internist
12 Ways to Fix iOS 13 Battery Draining Problem on iPhone