--- a/doc/doap.xml	Sat Jul 17 19:44:48 2021 +0200
+++ b/doc/doap.xml	Sat Feb 05 18:06:59 2022 +0100
@@ -51,6 +51,7 @@
     <implements rdf:resource="https://www.rfc-editor.org/info/rfc6120"/>
     <implements rdf:resource="https://www.rfc-editor.org/info/rfc6121"/>
     <implements rdf:resource="https://www.rfc-editor.org/info/rfc6122"/>
+    <implements rdf:resource="https://www.rfc-editor.org/info/rfc6331"/>
     <implements rdf:resource="https://www.rfc-editor.org/info/rfc6455"/>
     <implements rdf:resource="https://www.rfc-editor.org/info/rfc7233"/>
     <implements rdf:resource="https://www.rfc-editor.org/info/rfc7301"/>