Test the fix Set up email using mailcatcher, and set your stmphosts to that server Go to Site administration ▶︎ Plugins ▶︎ Authentication ▶︎ Manage authentication Select email based self registration as Self registration Log out or open a tab in another browser Create a user Check email Go to the confirmation url given Make sure you do not receive an exception Do the same for all these usernames A dot in the middle (e.g. "cameron.ball") Test trailing dots (e.g. "asdfjkl……" ) Create a username with underscore (_), hyphen (-), period (.) and at symbol (@). (e.g. "mark_-.@nelson....") For each one make sure you can sign up with no exceptions and all periods (.) are converted to %2E Regression testing Install the Moodle Mobile app in your mobile device Important, the Moodle site must be accessible from your mobile device In the Moodle site, enable authentication via e-mail (aka enable users to create their own accounts in the site) Ensure that advanced options like re-captcha are disabled Now, execute the following curl command to create a new user account in the site simulating to be the Mobile app (important, use a real user email account that you can open in your mobile device): curl 'http://192.168.1.103/m/stable_master/lib/ajax/service.php' --data-binary ' [{"index":0,"methodname":"auth_email_signup_user","args":{"username": "u2", "password": "moodle", "email": "myrealemail@gmail.com", "firstname": "asb", "lastname": "asdfasdf", "city": "Barcelona", "country": "ES", "redirect": "http://192.168.1.103/m/stable_master/admin/tool/mobile/launch.php?service=moodle_mobile_app&passport=xyz&confirmed=1"}}] ' | python -m "json.tool" If the user is correctly created, you will see a "success": true (among other data) You should receive then an e-mail with the account confirmation link, open the email in your mobile device and click the link The Mobile app will be launched (please, note that you will see an error or you won't be automatically logged in the site because the functionality is not yet implemented in the app) Go to the Moodle site, and confirm that the user account is confirmed Repeat the process (deleting the previous user) and now open the e-mail in your computer, you should see the standard Confirmation screen with a link to "Courses" (at the bottom you will see also a link to try to launch the app that won't work in desktop) Finally, create a new Moodle user account using the Moodle Web interface to ensure that no regressions were introduced with the changes