Apple has released iOS 12.4.1, tvOS 12.4.1, macOS 10.14.6. iOS 12.4.1 provides “important security and stability improvements, and is recommended for all users,” according to Apple. You can upgrade by opening the Settings app on your iPhone or iPad, choosing General --> Software Update.
watchOS 5.3.1 and tvOS 12.4.1 patches are also available. You can the Apple Watch update by going to the Watch app on your iPhone and selecting General —> Software Update. If your Apple TV doesn’t update automatically to tvOS 12.4.1, you can go to the home screen, go to Settings and choose Update Software under Software updates.
Apple has also released macOS 10.14.6. It: resolves an issue that may cause certain Mac notebooks to shut down during sleep; fixes an issue that may degrade performance when working with very large files; and addresses an issue that may prevent Pages, Keynote, Numbers, iMovie, and GarageBand from updating. To download it, go to the Settings app and click Software Update.