4 Update Your Apps
iOS 11.3 isn’t as huge of a jump as iOS 11 was, but it’s still a good idea to update all of your apps before installing the software. That way, you can mitigate any compatibility issues or bugs in orders apps. Just go to App Store > Updates and tap Update All.
On another note, if you’re updating from iOS 10, then you should be aware that iOS 11.3 will kill support for 32-bit applications. Most newer apps will already be in 64-bit, but it might be worth double-checking your favorites older apps. If you’re on iOS 10.3 or later (but not iOS 11), you can do so in Settings > General > About > Applications. Learn more about 32-bit apps here or continue to #3.