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IMAP Status and History

Protocol Status

The current IMAP base specification is RFC 3501: Internet Message Access Protocol - Version 4rev1. There continues to be active discussion regarding protocol extensions on the developer's mailing list. (For a list of IMAP-related draft, proposed, and other standards, see IMAP Documents.)

IMAP History

2003:

RFC 3501: Internet Message Access Protocol - Version 4rev1 completed, replacing IMAP4rev1 specification RFC 2060

2000:

IMAP Extensions Working Group started

1999:

IMAP4 Implementation Recommendations published

1998:

Two IMAP-related RFCs (on IMAP4 UIDPLUS extension and IMAP4 Namespace) published. Internet Mail Consortium holds MailConnect 4: IMAP and Advanced Extensions interoperability event.

1997:

Continuing clarifications to IMAP4rev1 specification as implementation experience grows. Ten IMAP-related RFCs published (see IMAP Documents: RFCs and drafts). Release of two IMAP clients, Netscape Messenger and Microsoft Outlook Express, that are integrated into the two most widely used WWW browsers: Netscape Communicator and Microsoft Internet Explorer, respectively. MailConnect 2: IMAP and ESMTP and MailConnect 3: IMAP and End-to-End Security interoperability events held by Internet Mail Consortium.

1996:

University of Washington hosts first and second IMAP meeting. Sun, Netscape, and many other vendors declare support for IMAP4. MailConnect 1: IMAP and MIME interoperability event held by Internet Mail Consortium. IMAP4rev1 specification (RFC 2060) completed.

1995:

First IMAP4 server released by CMU. IMAP4 C-Client and server implemented by UW.

1994:

IMAP4 RFCs published (1730-1733). IMAP4 approved as Proposed Internet Standard.

1993:

IMAP2bis I-D published in August. First VMS server implemented. IETF IMAP Working Group formed.

1992:

IMAP2bis server deployed by UW. Pine 2.0 released with IMAP support. CMU begins Andrew II/Cyrus project.

1991:

MIME support added, forming basis of IMAP2bis. IMAP3 offshoot published in Feb. (since abandoned)

1990:

Revised IMAP2 RFC published in August (1176). C-Client based Unix server in November.

1989:

Mark Crispin (original IMAP author) hired by U. Washington.

1988:

First IMAP RFC published in July (1064). Initial work on C-Client library.

1987:

IMAP2 defined; client & server updated. First Unix server implemented.

1986:

IMAP conceived at Stanford University. Interlisp client and DEC-20 server implemented.

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Last modified: Wed Jan 9 2008