Huawei Technologies RFC 6154 created an IMAP special-use LIST extension and defined an initial set of attributes. This document defines a new attribute, "\Important", and establishes a new IANA registry for IMAP folder attributes, which include the attributes defined in RFCs 5258, 3501, and 6154. This document also defines a new IMAP keyword, "$Important", and registers it in the registry defined in RFC 5788.