Apple has released iOS 12.1.1 for iPhones 5s and later, iPad mini 2 and later and iPod touch 6th generation or later. It is available as an over-the-air update and came with some new features such as expanded eSIM support, Live Photo capture during FaceTime calls, notification preview using haptic touch for iPhone XR, and more.
The latest iOS version promises better security than previous. It comes with a list of new security patches and features to protect your iPhone. It also fixed some serious issues from earlier updates: a fix for a Face ID issue, a fix for an issue with automatic time zone updates, and others. However, it brought new problems that affected millions of Apple product users, and it's rolling out even more while people are updating their devices.
Users are currently running into various problems and bugs. Based on the reports, the first problem users faced to is a various installation/downloading issues. The update download can get stuck on some models. Also, during the update to iOS 12.1.1, iPhones stuck in the Recovery mode. Hard reset of the devices could resolve that issue.
Another unpleasant surprise is a mobile data error. The device starts showing "No Service", and the only way to go online is to connect via Wi-Fi. Apple support recommendations to update carrier settings or hard reboot the handset don't solve the problem.
Apple is aware of those issues, consistently respond to users claims in social media and is working to resolve existing problems.