We have quite a number of concepts defined at VroniPlag Wiki that used to work before UDP, for example https://vroniplag.wikia.org/de/wiki/Konzept:Mdi_und_Gt50. It used to list all the pages that belonged both to the category Mdi and the category Gt50.
I have tried renaming everything to "Category" instead of "Kategorie", played around with formatting, no avail. The RSS feed does indeed show exactly the things I would expect so see like given here at the SMW page https://www.semantic-mediawiki.org/wiki/Concept:Semantic_MediaWiki_Cons_2012
Nothing seems to work, does anyone have any idea what I need to do? These lists were always extremely useful.