--- a/plugins/check_dns-delegation	Tue Jan 06 15:08:33 2015 +0100
+++ b/plugins/check_dns-delegation	Tue Jan 06 15:12:36 2015 +0100
@@ -16,6 +16,7 @@
 all responsible NS have the same serial number for their zones.
 
 Domains we are not responsible for are marked as B<critical>.
+Mismatching serial numbers are marked as B<critical>.
 
 The list of domains may consist of the following items: