Dig Into App Reviews
If you rely on your apps to get you through the workday you'll want to read app reviews before you install iOS 12.4.7 on your device(s).
App developers have rolled out a steady stream of updates in 2019 and many of these updates bring support for iOS 12, bug fixes, and new features. And while their intentions are good, there's a chance that they cause problems.
Before you install the update you'll want to head to the App Store and read reviews from iOS 12.4.7 users. If reviews are mostly positive you should be good to go.
If they're negative, you might want to wait for a new version of iOS 12 or for that developer to update the app before moving your device to iOS 12.4.7.