IMAP4 UIDPLUS extension
RFC 2359

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Network Working Group                                           J. Myers
Request for Comments: 2359                       Netscape Communications
Category: Standards Track                                      June 1998

                        IMAP4 UIDPLUS extension

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

IESG NOTE

   The IMAP extension described here assumes a particular means of using
   IMAP to support disconnected operation.  However, this means of
   supporting disconnected operation is not yet documented.  Also, there
   are multiple theories about how best to do disconnected operation in
   IMAP, and as yet, there is no consensus on which one should be
   adopted as a standard.

   This document is being approved as a Proposed Standard because it
   does not appear to have technical flaws in itelf.  However, approval
   of this document as a Proposed Standard should not be considered an
   IETF endorsement of any particular means of doing disconnected
   operation in IMAP.

Table of Contents

   1.   Abstract ..............................................    2
   2.   Conventions Used in this Document .....................    2
   3.   Introduction and Overview .............................    2
   4.   Features ..............................................    2
   4.1. UID EXPUNGE Command ...................................    2
   4.2. APPENDUID response code ...............................    3
   4.3. COPYUID response code .................................    4
   5.   Formal Syntax .........................................    4
   6.   References ............................................    4
   7.   Security Considerations ...............................    5
   8.   Author's Address ......................................    5
   9.   Full Copyright Statement ..............................    6

Myers                       Standards Track                     [Page 1]
RFC 2359                IMAP4 UIDPLUS extension                June 1998

1.   Abstract

   The UIDPLUS extension of the Internet Message Access Protocol [IMAP4]
   provides a set of features intended to reduce the amount of time and
   resources used by some client operations.  The features in UIDPLUS
   are primarily intended for disconnected-use clients.

2.   Conventions Used in this Document

   In examples, "C:" and "S:" indicate lines sent by the client and
   server respectively.

   The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
   in this document are to be interpreted as defined in "Key words for
   use in RFCs to Indicate Requirement Levels" [KEYWORDS].

3.   Introduction and Overview

   The UIDPLUS extension is present in any IMAP4 server implementation
   which returns "UIDPLUS" as one of the supported capabilities to the
   CAPABILITY command.  The UIDPLUS extension contains one additional
   command and additional data returned with successful APPEND and COPY
   commands.

   Clients that wish to use the new command in UIDPLUS must of course
   first test for the presence of the extension by issuing a CAPABILITY
   command.  Each of the features in UIDPLUS are optimizations; clients
   can provide the same functionality, albeit more slowly, by using
   commands in the base protocol.  With each feature, this document
   recommends a fallback approach to take when the UIDPLUS extension is
   not supported by the server.

4.   Features

4.1. UID EXPUNGE Command

   Arguments:  message set

   Data:       untagged responses: EXPUNGE

   Result:     OK - expunge completed
               NO - expunge failure (e.g. permission denied)
               BAD - command unknown or arguments invalid

Myers                       Standards Track                     [Page 2]
RFC 2359                IMAP4 UIDPLUS extension                June 1998

      The UID EXPUNGE command permanently removes from the currently
      selected mailbox all messages that both have the \Deleted flag set
      and have a UID that is included in the specified message set.  If
      a message either does not have the \Deleted flag set or is has a
      UID that is not included in the specified message set, it is not
      affected.

      This command may be used to ensure that a replayed EXPUNGE command
      does not remove any messages that have been marked as \Deleted
      between the time that the user requested the expunge operation and
      the time the server processes the command.

      If the server does not support the UIDPLUS capability, the client
      should fall back to using the STORE command to temporarily remove