Apple released updates to iOS 15.7.3 and earlier to provide more security.

In addition to the iOS 16.3 operating system released for new devices, the latest in older versions since iOS 12, iOS 15, macOS Monterey and macOS Big Sur has also been updated with an emphasis on security patches over each version as follows.

• iOS 12.5.7 for iPhone 5s, iPhone 6, iPhone 6 Plus, iPad Air, iPad Mini Gen 2, 3 and iPod Touch Gen 6.
• iOS 15.7.3 For iPhone 6s, iPhone 7, iPhone SE first generation and iPod Touch 7th generation.
• iPadOS 15.7.3 For iPad Air 2 and iPad Mini 4th Gen
• macOS Monterey version 12.6.3 and macOS Big Sur version 11.7.3

Most updates focus on security and fix vulnerabilities. Such as kernel level, Mail Exchange, Webkit for all eligible older devices are easy victims.