I can't find a way how to access diffs of course pages. History page of one cswiki course is not listing diff links. When I open some old version (say, this one) and try to use that link on lišit (It may _differ_ significantly from the current revision.: It should normally show the difference between that old version and current one.) I get some other diff (in this case, the diff of Main page).
Maybe these corrupted links are caused by trying to see diffs in EP namespace. Can you please add the support of diffs for course (and institution) pages?