http://www.newsweek.com/remove-ios-12-downgrade-restore-ios-11-ipsw-how-guide-1130818

Want to remove iOS 12 and downgrade to iOS 11? Here's how to restore your device to earlier software.

iOS 12 released on September 12, 2018 and though some were overjoyed to get access to the new MeMoji or group call features, others want the comfort of the previous iOS software. If you want to remove iOS 12 and go back to iOS 11, you’re in luck. The window for downgrades is still open. Below we’ve put together a guide for how to downgrade your iPhone or iPad to the earlier iOS 11.4.1.