While iOS 11 was meant to improve a bunch of new features and improvements to Apple’s iOS platform, it seems that it has had a pretty buggy launch, with quite a few users reporting various issues. One of the main issues seems to have to do with battery life, in which it was found that iOS 11 seems to be causing worse battery drain than before.
However the good news is that Apple could have fixed it. In the iOS 11.1 beta that was recently seeded to developers and beta testers, it looks like the update has improved upon battery life dramatically. In the test above conducted by iDeviceHelp, it shows that prior to iOS 11.1 and on various iPhones running iOS 11.0.3, users were getting around 4 hours or so of usage.
With iOS 11.1, that has jumped considerably to about 8 hours or so, doubling what was offered before. Of course your mileage may vary and how these tests were conducted could hardly be considered scientific, but it does seem to represent some pretty impressive battery gains. Interestingly enough the iPhone 7 Plus seems to have the shortest battery life out of the three devices tested, with the iPhone 8 Plus sporting the longest battery life.
In any case we expect that iOS 11.1 should be released to the general public soon, so if you have been holding off on updating to iOS 11, then perhaps waiting to iOS 11.1 might be a better idea.