Lockdown Mode will harden Apple devices against attacks for users who are at high risk of being targeted.
https://www.apple.com/newsroom/2022/07/apple-expands-commitment-to-protect-users-from-mercenary-spyware/
At launch, Lockdown Mode includes the following protections:
- Messages: Most message attachment types other than images are blocked. Some features, like link previews, are disabled.
- Web browsing: Certain complex web technologies, like just-in-time (JIT) JavaScript compilation, are disabled unless the user excludes a trusted site from Lockdown Mode.
- Apple services: Incoming invitations and service requests, including FaceTime calls, are blocked if the user has not previously sent the initiator a call or request.
- Wired connections with a computer or accessory are blocked when iPhone is locked.
- Configuration profiles cannot be installed, and the device cannot enroll into mobile device management (MDM), while Lockdown Mode is turned on.