Don't Install iOS 12.1.2 If You're Unprepared
If you haven't prepared yourself, or your device, for the move to iOS 12.1.2 you'll want to hold off on a download until you've done so.
It's impossible to predict how your device will handle the transition from iOS 11 to iOS 12 or iOS 12.0/iOS 12.0.1/iOS 12.1/iOS 12.1.1 to iOS 12.1.2 and that's precisely why we recommend doing a few minutes of prep work before you install the new software on your phone or tablet.
If you don't know where to start we've put together a guide that will walk you through the pre-installation process.
Spending a few minutes prepping for iOS 12.1.2 will go a long way toward preventing problems so make sure you take the time to properly prepare your device for the transition.