You Should Prepare for iOS 12.4
If you prepare for iOS 12.4 you could avoid a major headache.
While it might be tempting to just hit download and immediately move your phone from iOS 11 to iOS 12 or iOS 12.0/iOS 12.0.1/iOS 12.1/iOS 12.1.1/iOS 12.1.2/iOS 12.1.3/iOS 12.1.4/iOS 12.2/iOS 12.3/iOS 12.3.1 to iOS 12.4, know that a little prep work can go a long way toward preventing issues. iOS updates are unpredictable so you'll want to take your time.
If you don't know where to start we've put together a pre-installation guide that will take you through the steps we took before we installed iOS 12.4.
You don't need to follow every single step, but at the very least you'll want to make sure all of your data is backed up.
Data loss issues are rare, but it's better to be safe than sorry.