Though Apple released iOS 15.4.1 just under a couple of weeks ago, many iPhone users still running an earlier version of iOS 15 may be at risk due to a major security flaw that Apple says "may have been actively exploited". Take a look at what is new in Apple's latest version of its iPhone operating system.
https://www.notebookcheck.net/iOS-15-4-1-3-surprising-reasons-why-iPhone-users-should-update.613348.0.html