On the website description is written that att remover is included. As I had the Linux version it worked, when I had to switch to Windows the dll seems to be simply missing despite the annoucement ... This is a major function that allow to cut email size to the minimum (plain text). Thanks
Are you sure you loaded it ? It should be there in \Program Files\GNU\Claws Mail\lib\claws-mail\plugins\att_remover.dll
Attachment Remover is part of the release.