User Password Policies

Changing your Password restrictions or Prevent use of breachable passwords settings (found at Settings > Users > User Settings) will not result in your existing users being forced to change their current passwords. Only new or changed passwords will have the new requirements enforced.

Also note that if you would like to require some users to change their passwords, you can do so by enabling the Require password change on next login setting found on the Authentication sub-tab when editing a user.