Noted, and I already fixed the issue by going to some posted links about allowing numiric username for agents, my only issue for now is when I want to update agents permissions (I'm using LDAP), it still says username has invalid characters, then I have to add additional char in their username so I can update permissions, and then once done, I go to db table remove the additional charcter manually.
How can I fix this small issue please, I think it's from staff.inc.php