The Apple Security Update is required to prevent an iMessage vulnerability.
On September 13, 2021, Apple announced a new zero-day, zero-click vulnerability in all types of Apple devices, including Macs, iPhones, iPads, and watchOS. The flaw has been called FORCEDENTRY. Apple has updated its software for iPhones to address a critical vulnerability.
Updates are required.
All Apple devices should be updated as soon as possible using View Apple Security Updates in Actions. Additional information from Apple is also available in Actions.