Heyo  My users often use special characters in the display name. My forum is in Polish, so letters with litte tails like "ąśłćżźłęęąźćłę" are normal. I know there is a setting called "Allowed characters in display names" but it is too restrictive.

Is there a chance to add a "Disallowed characters in display names" field? That would make things easier. 

 

Not to say this isn’t a valid feature request, but for now you could also try the ban settings to disallow certain characters. 

Typically, when you want to restrict characters in usernames you want to allow a subset of valid characters and not allow anything else, and to that end it would be super tedious to try to outline every disallowed character (because multibyte unicode means there are literally over a million possible characters).

To disallow certain specific characters, I would go with opentype's suggestion.

For your use case, you can use this regex (which I got from stackoverflow):

[AaĄąBbCcĆćDdEeĘęFfGgHhIiJjKkLlŁłMmNnŃńOoÓóPpRrSsŚśTtUuWwYyZzŹźŻż]

or if you're happy with what you have now, just stick with it. It is a set once and forget thing anyways.

@bfarber thank you for reply. You have right. I use @opentype suggestion.