This module adds email verification to the user accounts when changing their email.
When a user changes their email address, this module will temporarily save the new value and check if it is already used. If it is not already used, it will send a verification email (configurable) to the new email address with a one-time verification link. Upon using that link the logged in user's email address will be changed to the temporarily stored new address, provided that they are the correct currently logged in user.