Ignore invalid Push-Dont-Notify values

Author: rfc2822

content.mkd

@@ -365,6 +365,8 @@ Because URLs are not per se canonical, registration URLs MUST be provided in the
 
 Multiple values can be provided as a list and/or using multiple lines as described in {{Section 5.2 of RFC9110}}. If the asterisk is used, other values MUST NOT be sent.
 
+A server MUST ignore invalid values.
+
 Example 1:
 
 ~~~http-message