I've installed Mantis 19.2. and configured it described in the manual. When I try to signup a new account I've got the error 805 " The username is invalid. Usernames may only contain letters, numbers, spaces, hyphens, and underscores.".
I tried to fix the problem by applying the patch described in some bugfixes:
 # --------------------
 # Return true if the currently user is the anonymous user
 function current_user_is_anonymous() {
 if ( auth_is_user_authenticated() ) {
         return current_user_get_field( 'username' ) == config_get( 'anonymous_account' );
 } else {
         return false;
But it isn't working yet. What did I miss? Any suggestions?