Remove or disable it. It were not om my script
You can pass UTF8 code via the config but the the script has to written with API and not lua standard functions if you are manipulate the string by using a substring etc
If the value is only used for direct comparison or send to the AIP it works without problem
You can look at at alphabet checker with only aö below it work but because a missing UTF8StringLength a garbage empty character is added in the end
I have asked ganja1447 for the missing function
http://project-gc.com/Challenges//1994