i downloaded the editor this morning; so it's the latest version ;).

 

i have no problems with that link; just postet some ü ä ö ß for you
http://dnn3.cutesoft.net/DNNEditDemo/tabid/92/Default.aspx

and you will see, in the final html sourcecode; after an update, you will not find any ü ä ö or ß.