I run a forum on MyBB, but alot of the users who are on it have come from an vBulletin board. Anyway, a User wants to use certain characters in their username which VBulletin has allowed, but which MyBB is claiming to be invalid. Is there a way to force these characters to work (i tried changing it manually in the AdminCP but it still won't let me) or will i have to tell said person they will have to come up with a new Username?