IMAP4 Keyword Registry
RFC 5788

Internet Engineering Task Force (IETF)                       A. Melnikov
Request for Comments: 5788                                   D. Cridland
Category: Standards Track                                  Isode Limited
ISSN: 2070-1721                                               March 2010

                         IMAP4 Keyword Registry

Abstract

   The aim of this document is to establish a new IANA registry for IMAP
   keywords and to define a procedure for keyword registration, in order
   to improve interoperability between different IMAP clients.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5788.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Melnikov & Cridland          Standards Track                    [Page 1]
RFC 5788                 IMAP4 Keyword Registry               March 2010

Table of Contents

   1. Introduction ....................................................2
   2. Conventions Used in This Document ...............................2
   3. IANA Considerations .............................................3
      3.1. Review Guidelines for the Designated Expert Reviewer .......4
      3.2. Comments on IMAP Keywords' Registrations ...................5
      3.3. Change Control .............................................5
      3.4. Initial Registrations ......................................6
           3.4.1. $MDNSent IMAP Keyword Registration ..................6
           3.4.2. $Forwarded IMAP Keyword Registration ................7
           3.4.3. $SubmitPending IMAP Keyword Registration ............8
           3.4.4. $Submitted IMAP Keyword Registration ................9
   4. Security Considerations ........................................10
   5. Acknowledgements ...............................................10
   6. References .....................................................10
      6.1. Normative References ......................................10
      6.2. Informative References ....................................11

1.  Introduction

   IMAP keywords [RFC3501] are boolean named flags that can be used by
   clients to annotate messages in an IMAP mailbox.  Although IMAP
   keywords are an optional feature of IMAP, the majority of IMAP
   servers can store arbitrary keywords.  Many mainstream IMAP clients
   use a limited set of specific keywords, and some can manage (create,
   edit, display) arbitrary IMAP keywords.

   Over the years, some IMAP keywords have become de-facto standards,
   with some specific semantics associated with them.  In some cases,
   different client implementors decided to define and use keywords with
   different names, but the same semantics.  Some server implementors
   decided to map such keywords automatically in order to improve cross-
   client interoperability.

   In other cases, the same keywords have been used with different
   semantics, thus causing interoperability problems.

   This document attempts to prevent further incompatible uses of IMAP
   keywords by establishing an "IMAP Keywords" registry and allocating a
   special prefix for standardized keywords.

2.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [Kwds].

Melnikov & Cridland          Standards Track                    [Page 2]
RFC 5788                 IMAP4 Keyword Registry               March 2010