I think it may be from TL1 up now to mute a user. Having a quick check with a TL0 test user, the option doesn’t appear in the user-to-be-muted’s profile, and navigating to their Preferences/User tab just gives this:
There is a green tick against TL0 for muting users in Trust Level Permissions Reference, so that may need updating.
Also, I believe the ignore feature is available from TL2 up (by default)