This plugin does 3 things
1) It will check you don’t have a username called “admin” which is asking to be hacked
2) It will allow you to reset all passwords, with an password reset link sent to all users to warn them.
Following a couple of reviews from v7.0 the plugin will allow you to set the email from address, name, subject and message
3) You can also change the SALTS which forces a logout of all users.