Hi cssyeah,
thanks for your feedback. The problem is that the template overrides (templates/ja_purity_iv/html) are not recognized. When I rename the html directory, there is no change in the frontend.
I have a second installation of Purity IV with all demo data. When I rename the override directory category (templates/ja_purity_iv/html/com_content/category), the change is also visible in the frontend.