It seems as though every new iOS updates brings various complaints from users ranging from performance setbacks to battery life issues, and iOS 11.4 is no exception. iPhone users running iOS 11.4 right now have been complaining in droves that battery life has suffered after the update.
Reports indicate that there are over 33 pages of complaints on the Apple website from users suffering from varying levels of battery drain since updating to iOS 11.4. The main complaint is standby battery life has been significantly impacted for many of these users. One user claims that before iOS 11.4 he was able to go a full day without charging his iPhone 6, but after the update, the phone only lasts about half a day. The user maintains the only change to his device was the update to iOS 11.4.
Another user claims that the Settings app shows that Personal Hotspot is using about half of the battery life, yet it has never been turned on. That user claims to have to charge the iPhone every 2-3 hours. Another user having similar issues claims that the iPhone was updated to iOS 11.4, charged to 100%, rebooted and left in standby for four hours. The battery indicator reportedly dropped to 40% over that time.
Some users that have tried the iOS 12 beta claim that the update solved their battery life problems. The catch is that as a beta OS it could bring other issues, like app instability or incompatibility. iOS 11.4.1 is in beta testing right now and will land before iOS 12 does this fall. Some speculate that the 11.4.1 update will address the battery drain issue, something that Apple has yet to confirm.
Apple's iOS 11.4 was the first update to iOS to mention restrictions that would make it harder for police and hackers to crack the lock codes of the device. That USB restricted mode will be fully baked into iOS 12.