Setup Setup a LDAP server and setup the LDAP authentication plugin. If you don't have LDAP server you can use docker. For instance: docker run -p 389:389 --name my-openldap-container --hostname ldap.example.org --env LDAP_REPLICATION=true  --detach osixia/openldap:1.2.0 docker run -p 6443:443 --name phpldapadmin-service --link my-openldap-container:ldap-host --env PHPLDAPADMIN_LDAP_HOSTS=ldap-host --detach osixia/phpldapadmin:0.7.1 With this two commands you already have a nice LDAP server and PHPLdapadmin to manage. You can go to https://localhost:6443/  in your browser login: cn=admin,dc=example,dc=org password: admin Now, you can create a new user into your LDAP and let the email field empty. To do that you could import a new user with the import option and add this value in the text area: dn: cn=perry mason,dc=example,dc=org cn: perry mason gidnumber: 500 givenname: pmason homedirectory: /home/users/pmason objectclass: inetOrgPerson objectclass: posixAccount objectclass: top sn: mason uid: pmason uidnumber: 1042 userpassword: {MD5}gnzLDuqKcGxMNKFokfhOew== In Moodle you can setup LDAP settings in http://YOURMOODLESITE/admin/settings.php?section=authsettingldap host_url: ldap://localhost:389 ldap_version: 3 start_tls: no bind_dn: cn=admin,dc=example,dc=org bind_pw: admin user_type: Default contexts: dc=example,dc=org search_sub: yes passtype: Plain text In Moodle you have to allow extended characters in usernames. To do that: Go to Site administration / Security / Site security settings and enabled extendedusernamechars setting. For your LDAP settings ensure you have  correctly  mapped the email address by entering a value in ‘Data mapping (Email address)’ that exists on the LDAP server and set ‘Update external (Email address)’ to ‘On update’ and 'Update local (Email address)' to 'On every login'. If you are using the openldap in the example, then the correct field for email in the ldap is " mail ". Open mailhog, mailcatcher or similar tool configured to capture emails from your Moodle site (or set one up).  Test 1: Update user profile when the mail field is empty in LDAP Log into your Moodle site as one of your LDAP users. Following the previous example, you could login with: username: perry mason password: 12345 Change your email in the user profile screen. Go to your inbox in your mailhog, mailcatcher or similar tool. Confirm you have received an email for confirmation of email with a link inside. Visit the previous link. Expected result:   the email has been updated in Moodle and in LDAP. Test 2: No PHP notices when the field does not exist on the LDAP Log in as an admin in Moodle. Go to setup LDAP settings in Moodle. Configure and incorrectly email field in the data mapping section: For instance:   field_map_email: emailwrong field_updateremote_email: On update Log out. Log into your Moodle site as another one of your LDAP users. Following the previous example, you have to create an account in your LDAP server. You can use  http://localhost:6443/  to create a new account. Change your email in the user profile screen. Go to your inbox in your mailhog, mailcatcher or similar tool. Confirm you have received an email for confirmation of email with a link inside. Visit the previous link. Expected result: There are not PHP notices.