diff --git a/Makefile b/Makefile
index 16fdec3a6..d585b7b8d 100644
--- a/Makefile
+++ b/Makefile
@@ -96,7 +96,7 @@ $(DATESTAMP):
 
 ### Regeln für den XSLT-Prozess ###
 
-build/%.html : VFLAGS_OUT=$(VFLAGS) --schema xsd/xhtml1-strict.xsd
+build/%.html : VFLAGS_OUT=$(VFLAGS) --relaxng html5-syntax/html5.rng
 build/news.html: $(WWW_CCC_DE_UPDATES) $(CALENDAR_SUMMARY) $(DATESTAMP)
 build/news-rss.xml : STYLE=xsl/rss.xsl
 build/news-rss.xml : NOVALID_IGNORE:=true