A SIP Response Code for Unwanted Calls
RFC 8197

Received changes through RFC Editor sync (created alias RFC 8197, changed abstract to 'This document defines the 607 (Unwanted) SIP response code, allowing called parties to indicate that the call or message was unwanted.  SIP entities may use this information to adjust how future calls from this calling party are handled for the called party or more broadly.', changed standardization level to Proposed Standard, changed state to RFC, added RFC published event at 2017-07-13, changed IESG state to RFC Published)