Hello,
I've updated the file, and it works now. The file is at:
\src\vendor\dokuwiki\utf8\utf8.php
The missing ones are:
// Missing accented Greek
'ά'=>'a','Ά'=>'A','έ'=>'e','Έ'=>'E','ί'=>'I','Ί'=>'I','ή'=>'i','Ή'=>'I','ύ'=>'y','Ύ'=>'Y','ώ'=>'o','Ώ'=>'O','ό'=>'o','Ό'=>'O',