What a Catalina Mac 15.6 that is needed for my phone? And why is that?
Who is sending this information and installation to my phone.
Question marked as
By default, an iPhone will check for iOS and app updates, and will offer the installation of the updates.
iOS 15.6 is the current iOS version for iPhone.
Catalina is a recent macOS version for Mac, and not used with iPhone.
Apple has fixed various security issues, including with iOS 15.6, and some of those issues fixed were common with iPhone, iPad, and Mac software, so patch notices can include mentions of fixes for the other platforms.
Applying iOS and app updates as they become available helps maintain the security of your iPhone and your data.