From Forbes:
Apple released iOS 17.7 on Monday, along with a warning to update your iPhone. That’s because iOS 17.7 comes with a large list of 16 important security fixes for all iPhone users.
The company doesn’t provide much information about what’s fixed in iOS 17.7 to give people time to update and prevent attackers getting hold of the details. The iOS 17.7 update “provides important security fixes and is recommended for all users,” Apple said. Apple’s iOS 17.7 upgrade was released alongside iOS 18, including many of the same security fixes. The iOS 17.7 update is for iPhone users who want to wait before upgrading to the latest Apple software.