Blogger iAppleBytes conducted tests on different models (iPhone SE, iPhone 6S, iPhone 7, iPhone 8, iPhone XR and iPhone 11)to find out. He conducted Geekbench tests on each of the smartphones and compared their results with iOS 13.3.1 and iOS 13.4. The blogger also shared his detailed review of how charging consumption has changed in iOS 13.4.
The results were interesting. Almost all models started to use up charging a little faster immediately after upgrading to iOS 13.4. However, after a while everything got better, and the iPhone 7 and iPhone 8 even started working longer.
Don't panic if your iPhone starts to run down faster after installing iOS 13.4. In about a 2-3 days, everything will be back to normal.