diff --git a/Documentation/install-webdoc.sh b/Documentation/install-webdoc.sh
index e51a40eecdc6535e29893545f01b80e60dab2ea5..d593ab988be48ba9f9d910e9fdbc73e2837241cc 100755
--- a/Documentation/install-webdoc.sh
+++ b/Documentation/install-webdoc.sh
@@ -4,7 +4,7 @@ T="$1"
 
 for h in *.html howto/*.txt howto/*.html
 do
-	diff -u "$T/$h" "$h" || {
+	diff -u -I'Last updated [0-9][0-9]-[A-Z][a-z][a-z]-' "$T/$h" "$h" || {
 		echo >&2 "# install $h $T/$h"
 		rm -f "$T/$h"
 		mkdir -p `dirname "$T/$h"`