diff --git a/testdata/dot-ref/color.dot b/testdata/dot-ref/color.dot
index 1452e2e..b8d76a7 100644
--- a/testdata/dot-ref/color.dot
+++ b/testdata/dot-ref/color.dot
@@ -1,7 +1,7 @@
 #!/usr/local/bin/dot
 #
 # Class diagram 
-# Generated by UmlGraph version 5.0 (http://www.spinellis.gr/sw/umlgraph)
+# Generated by UMLGraph version 5.1 (http://www.umlgraph.org/)
 #
 
 digraph G {