Apple in iOS 16 added a new Rapid Security Response feature that's meant to make it quicker and easier for the company to deploy security improvements to iPhone users without a full iOS update. By default, Rapid Security Responses are installed automatically, but Apple has implemented a way to remove them.
In an updated support document shared today, Apple says that you can remove a Rapid Security Response from your device by going to Settings > General > About, tapping the iOS version, and then tapping Remove Security Update.
Apple says you can then reinstall the Rapid Security Response at a later date, or wait for it to be installed permanently as part of a standard software update. It is not clear why a Rapid Security Response would need to be removed, but it's nice that users will have the option.
So it seems like the Rapid Security Responses are removable until they are baked into the next iOS update. pic.twitter.com/xAcHCHuIPS — Aaron (@aaronp613) September 12, 2022
There is also a toggle for turning off automatic installation of Rapid Security Responses, which then allows them to be downloaded manually.
Source: Macrumors