I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments.

A new sentence was added to Security Considerations in version 20. I believe it, combined with the previous sentence, will help clueful developers understand that there may be a need to add HMAC processing even if there is no SRH header. Thanks. None of the other changes in the update appear to affect security considerations.