DID YOU RECEIVE an unfamiliar security alert urging you to update your iPhone, iPad, or Mac immediately? Not everyone did, but this wasn’t a fake. It was Apple’s first use of Rapid Security Response, a new type of software update designed to deliver important security improvements between the usual software updates — for example, improvements to Safari, the WebKit framework stack, or other critical system libraries. Rapid Security Response may also be used to mitigate some security issues more quickly, such as issues that may have been exploited or reported to exist in the wild. New Rapid Security Responses will be delivered only for the latest version of iOS, iPadOS, and macOS — beginning with iOS 16.4.1, iPadOS 16.4.1, and macOS 13.3.1. By default, devices will allow Rapid Security Responses to be applied automatically and, if necessary, will prompt you to restart the device. Find out more at https://support.apple.com/en-us/HT201224.