iOS 11 Battery Life

Ever since the upgrade to iOS 11, my battery life on my iPad Pro 12.9 late 2015 model has been horrible. With iOS 10, I always got 10 or more hours with the device, but these days I'm lucky to see 4-5 hours of light use before its back on the charger. My iPhone 7 is similarly afflicted though to a lesser extent. My iPad also sputters and lags on the home screen for several minutes when you first unlock it as though it's an 8 or 9 year old device. Both devices are running the latest version of iOS 11.

I've been exclusively an Apple customer for almost 10 years now because of the past reliability of their devices (which you expect when paying such a high premium), but Apple MUST fix iOS 11. If anybody has a magic solution to the above issues, I would be eternally grateful, but I'm assuming all of this is related to poor support for devices that predate the newest iOS release.

Apple has lost me as a customer if they think I'm shelling out $1000+ for a new iPad Pro with every major iOS release.