I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review. Document editors and WG chairs should treat these comments just like any other last call comments. Summary: This document extends the SIEVE mail filtering language (RFC 5228) with capability similar to SPECIAL-USE capability of the IMAP protocol. This extension to SIEVE does not have any new issues related to operations and manageability.