Special characters are not supported (german)

Hi!

The plugin works fine on my site – easy to setup, everything is fine. Thinking about going for PRO…

But one thing: My site is in german, so we have special characters like this:

? ? ü ? ? ü ?

I entered the word “?ndern” to the filter list but this did not work. Any idea how to get this done?

https://www.ads-software.com/plugins/wp-content-filter/