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. The draft defines a set of extensions to the VALARM component of iCalendar. The document is short and well written, its Security Considerations and Privacy Considerations sections are sensible. I found the document ready. Nit: I would recommend adding a sentence to the Security Considerations section saying that these VALARM extensions inherited security properties of iCalendar [RFC5545].