path: root/imap/docs/RELNOTES

/* ========================================================================
 * Copyright 1988-2008 University of Washington
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
 * ========================================================================
 */

Updated: 16 December 2008

imap-2007e is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users
plus a security fix for users of the RFC822BUFFER routines.


Updated: 29 October 2008

imap-2007d is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users
plus a security fix for users of tmail or dmail.


Updated: 25 March 2008

imap-2007b is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 2 January 2008

imap-2007a is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 20 December 2007

imap-2007 is a release corresponding with the release of Alpine 1.0.
The primary focus of the imap-2007 release is bugfixes and reliability
improvements.  This includes:
 . fixes to problems discovered between the Alpine 0.99999 pre-release
    and Alpine 1.0
 . fixes to the mix driver to timing race problems uncovered by Timo
    Sirainen's imaptest suite.  imap-2007 using the mix format is
    believed to pass imaptest completely.

A new function, utf8_csvalidmap(), has been added for the benefit of
Alpine to use in examining UTF-8 text and determining efficiently
whether it can be downgraded to a legacy charset.  If you develop an
MUA, this may be useful for you too, although you'll have to read the
source code to see how to use it.  The purpose of the "not-CJK" bit is
to prevent messages being downgraded to a CJK charset if all they have
in that charset are some special punctuation.


Updated: 5 September 2007

imap-2006k is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.

The primary focus of this maintenance release is to correct deadlock
issues.  There were two major causes of the deadlocks:
 . a change in imap-2006i attempted to resolve a glibc mutex-based
   deadlock in imapd's signal handler, but ended up worsening the problem.
 . a bug in the mbx driver, introduced as part of the UIDPLUS work in 2006,
   applied an mbx-style lock briefly on a traditional UNIX format mailbox.
   If the traditional UNIX format mailbox was already locked by some other
   process, the result would be a deadlock of both processes.

imapd's signal handling logic is rewritten to avoid the mutex issue, and
the mbx driver is fixed so that mbx-style locks are only applied to mbx
format mailboxes.

imapd now supports the WITHIN extension.


Updated: 14 June 2007

imap-2006j is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 5 June 2007

imap-2006i is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.

imapd now supports the CHILDREN and ESEARCH extensions.

imapd's attempt to return COPYUID/APPENDUID information for a traditional
UNIX (and MMDF) format mailbox when the mailbox is open by another process
has been declared to be a failure and is now revoked.  It was subject to a
timing race, loss of which involved an expensive reset of the mailbox's UID
regime.  Any imapd COPY or APPEND to a traditional UNIX or MMDF format that
is open by some other process will now no longer return COPYUID/APPEND.
Although this is technically in violation of RFC 4315, there is a loophole
in that document and the timing race/performance problem is worse.


Updated: 4 April 2007

imap-2006h is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 30 March 2007

imap-2006g is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 30 January 2007

imap-2006f is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.

For the benefit of multi-threaded applications, use of strtok() has been
abolished in the c-client library.  imapd and ipop3d stuff use it though.
The TOPS-20 and VAX/VMS ports still use strtok() since they don't use UNIX
threads.

This version has been test-built on Linux, Mac OS X, NeXT, Windows XP,
TOPS-20, and VAX/VMS.  This will probably be the last test-build on VAX/VMS
since the system I use for that purpose is being shut down.  I have no way
to test-build on DOS, legacy Mac OS (OS 9 and earlier), OS/2, or Windows CE;
and the builds on those systems are probably broken.


Updated: 26 January 2007

imap-2006e is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 6 December 2006

imap-2006d is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.

The decomposition mapping, title-case mapping, and character widths tables
have been updated to comply with the Unicode 5.0 standard.

Prototypes for the utf8aux.c functions have been moved to a new utf8aux.h.

The general c-client modules now include c-client.h instead of the individual
files.  Use of c-client.h instead of individual include files insulates
against future shuffling of include files.


Updated: 23 October 2006

imap-2006c is a maintenance release, consisting primarily of bugfixes to
problems discovered in the release that affected a small number of users.

By popular request, if a user has a mix (or other dual-use) format INBOX,
it will no longer be listed as \NoInferiors.  It's a bad idea to depend
upon this due to the case ambiguity issue, but it's there.


Updated: 26 September 2006

imap-2006b is a maintenance release, consisting entirely of bugfixes to
problems discovered in the release that affected a small number of users.


Updated: 15 September 2006

imap-2006a is a maintenance release, consisting entirely of bugfixes to
problems discovered in the release that affected a small number of users.

If it is necessary to build IPv4-only on one of the ports that has IPv6
preconfigured (ldb, lfd, lmd, lrh, lsu, osx, oxp), this can be done by
using IP6=4.  You can't do IP=4 in the build command directly since these
ports set IP themselves; however, now instead of setting IP=6 they now set
IP=$(IP6).


Updated: 30 August 2006

imap-2006 is a major release.  Programs written for imap-2004g should
build with this version with minor or no modification.  imap-2005 was not
released except as development snapshots.

imap-2006 contains major extensions to its Unicode support.  Searching and
sorting are now done with strings canonicalized to titlecase and decomposed
form.  Among other things, this means that Latin letters with diacriticals
will now sort with the basic Latin letter, and case-independent searching of
such letters (e.g., German umlauts) now works.  Previously, sorting was done
strictly by Unicode codepoint, and case-independence only worked with ASCII.

imapd now supports the UIDPLUS extension for mailboxes in unix, mmdf, mbx, mx,
and mix formats.  UID EXPUNGE is fully implemented.  Note that UIDPLUS is not
supported in the little-used drivers (mh, mtx, tenex) in which meaningful
APPENDUID/COPYUID data can not be returned.  Refer to bugs.txt for more
details.

The new mix format is a dual-use mailbox format designed for performance and
reliability with large mailboxes.  mix is documented in file mixfmt.txt.

SSL/TLS certificate validation on UNIX now checks the alternative names in the
certificate if the CN does not match.

The new /tls-sslv23 flag in a mailbox name causes a TLS session to use the
(incorrect) SSLv23 client method instead of the TLSv1 client method.  Some
broken servers use the SSLv23 server method, and this flag works around that
problem.  WARNING: use of this flag will cause TLS negotiation to fail with
a server which uses the proper TLSv1 server method.  Additionally, there are
known security risks in SSLv2; so users should be suspicious if this switch
suddenly becomes necesary.

The silly mailbox flag combination /ssl/tls is now rejected as an invalid
remote specification.  Previous versions tried to negotiate TLS over an SSL
session; even if the server permitted such a thing it couldn't work.

The memory management of several drivers has been redesigned to consume less
memory and hopefully be faster.

The private.data member of the MESSAGECACHE (elt) has been replaced with
a union that contains private.spare.data and private.spare.ptr, the latter
being a pointer.

A new FT_RETURNSTRINGSTRUCT flag has been added for mail_fetch_body() and
mail_fetch_text() calls.  If this flag is set, *and* if the function returns
NIL, then the requested string data is available on a stringstruct on
stream->private.string.  This is a special hack for the IMAP and POP servers
and is subject to incompatible change.  The result is a major performance
improvement in the servers with the mbx driver, particularly with large
messages.


Updated: 15 September 2005

imap-2004g is a maintenance release, and consists solely of a bugfix to
quoted string handling in the mailbox name parsing routine.


Updated: 15 August 2005

imap-2004f is a maintenance release, and consists solely of a bugfix to
the TCP code.

Also included is a new version of the UNIX SSL/TLS routines that allows the
SSL/TLS certificate validation client code to validate alternative names in
server certificates.  This code has not been thoroughly regression-tested but
is believed to work.  To use this new code instead of the old support:
	cd imap-2004f/src/osdep/unix
	mv ssl_unix.c ssl_unix.old
	mv ssl_unix.new ssl_unix.c
Then rebuild.


Updated: 21 June 2005

imap-2004e is a maintenance release, consisting entirely of bugfixes.

There are no user-visible functional enhancements in this version.


Updated: 20 April 2005

imap-2004d is a maintenance release, released concurrently with Pine
4.63, and consists primarily of bugfixes

There is now a workaround for RedHat breaking flock().  However, since
RedHat has said that they don't support flock(), there is no guarantee
that they won't break it in the future.  So you may want to consider some
other Linux distribution or BSD instead.  See:
	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=123415
for the gruesome details.

There are no user-visible functional enhancements in this version.


Updated: 18 January 2005

imap-2004c is a maintenance release, released concurrently with Pine
4.62, including fixes to quoted-printable encoding and CRAM-MD5
authentication.

NNTP proxy in imapd now supports the LIST and LSUB commands.

There are no other user-visible functional enhancements in this version.


Updated: 29 November 2004

imap-2004b is a maintenance release, consisting primarily of bugfixes.
Programs written for imap-2004a will build with this version without
modifification.

There are new ports for Solaris with Blastwave Community Open Source
Software (gcs) and Mandrake Linux (lmd).

SET_SNARFINTERVAL now controls how frequently local drivers will move new
mail from the mail spool as well as from a maildrop.  Maildrops are still
tied to a minimum interval of 1 minute, but there is now no minimum for the
spool file.

Character set conversions now map non-breaking space to space if the
destination character set doesn't have nbsp.  JIS Roman yen sign is now
mapped to Unicode yen sign.

There are no user-visible functional enhancements in this version.


Updated: 8 July 2004

imap-2004a is a maintenance release, consisting primarily of critical
bugfixes.  Programs written for imap-2004 will build with this version
without modification.

imapd now has a supported NNTP proxy capability.  If the file /etc/imapd.nntp
exists, the contents of that file are used as the host name of an NNTP
server which will be used whenever a #news. name is used.  For example, if
/etc/imapd.nntp contains nntp.example.com, and the IMAP client SELECTs or
EXAMINEs the name #news.comp.mail.imap, what will actually be opened in
imapd is {nntp.example.com/nntp}comp.mail.imap

The OSF/1 port (Digital UNIX, Tru64) now uses flocksim instead of flcksafe.
Some cretin decided to delete the winning flock() call and make flock() use
the losing fcntl() call instead.

The unix[nt] and mmdf drivers now prevent mail_append() from writing Status:,
X-Status:, X-UID, X-IMAP[base]:, and X-Keywords: header lines to a
traditional UNIX or MMDF format mailbox.  If any such lines are in the
text supplied to mail_append(), they will be quoted by prefixing with
"X-Original-" (e.g. Status: will become X-Original-Status:).

There are no user-visible functional enhancements in this version.


Updated: 10 May 2004

imap-2004 is a major release.  Programs written for imap-2002e should
build with this version with minor modification.  imap-2003 was not
released except as development snapshots.

mailutil has three new commands: delete, rename, and prune.

IPv6 support now exists for UNIX and W2K.  It is the default in W2K builds.
On UNIX, add "IP=6" to the make command line.  Windows IPv6 support is
only for W2K builds.

The NNTP driver now supports NNTP SASL and TLS.

The ldb (Debian) and lrh (RedHat) ports now look for mlock on
/usr/sbin/mlock instead of /etc/mlock.

imapd now supports the LITERAL+ and SASL-IR initial-response extensions.

The IMAP driver has some additional checks to reduce the amount of network
traffic, including executing "silly searches" (searches of sequence numbers
only) locally.

The IMAP, POP, SMTP, and NNTP drivers now have diagnostic code to provide
better information about servers which violate SASL's empty challenge
requirements (e.g. with the PLAIN mechanism).

There is a new mail_fetch_overview_sequence() function which is like
mail_fetch_overview() but takes a sequence number string as an argument.
There should have been a flags argument and FT_UID bit as in all the other
mail_fetch_???() functions but compatibility with the past... :-(

The overview_t callback (from mail_fetch_overview()) now has a fourth
argument which contains the message sequence number (as opposed to the UID
which is in the second argument).  It turned out that some applications were
calling mail_msgno() (which can be moderately expensive) to get the sequence
number, and c-client already knew it.

Many declarations which are completely internal to a driver have been removed
from the driver .h file, and in those cases where there are no external
declarations left the .h file has been eliminated entirely.  As part of this,
the mbox driver routines are now incorporated with the unix driver routines
as opposed to being a separate file.  The mbox driver still needs to be lunk
in order to get the mbox functionality.


Updated: 27 August 2003

imap-2002e is a minor release, released concurrently with Pine 4.58, and
contains primarily bugfixes.  Programs written for imap-2002d will build
with this version without modification.

The NNTP client code now tries to perform better with legacy NNTP servers
which do not comply with the current NNTP protocol specification draft, most
notably Netscape Collabra.

Delivery notifications now work reliably with SMTP servers that support it.

The following changes are primarily of concern to developers and power users:

There is a "limited advertise" option in env_unix.c which, if set, will only
advertise the user's own namespace and the #shared/ namespace.

It is now possible to build the IMAP toolkit with a separate SSL KEY file
from the certificate file (SSLKEYS vs. SSLCERTS).

A new BODY structure element, sparep, is available for the main program to
use as a pointer for its own purposes; as well as a SET_FREEBODYSPAREP
function, similar to SET_FREEENVELOPESPAREP, SET_FREEELTSPAREP, etc.


Updated: 28 May 2003

imap-2002d is a minor release, released concurrently with Pine 4.56, and
contains primarily bugfixes.  Programs written for imap-2002 should build
with this version without modification, with one exception.  That exception
is the ngbogus envelope flag, which stopped being used in imap-2002c and is
now gone for good.

The NNTP newsgroup listing code now tries to use wildmats on the NNTP server,
which should result in better performance especially on slow lines.  It is
also once again permitted to log in on NNTP servers when /loser is set.

imapd now supports the UNSELECT command.

A new envelope flag, imapenvonly, indicates that the envelope in a
MESSAGE/RFC822 BODY structure only has the IMAP envelope components and
not the additional components from c-client: Newsgroups, Followup-To,
and References.


Updated: 7 April 2003

imap-2002c is a minor release, released concurrently with Pine 4.55, and
contains primarily bugfixes.  Programs written for imap-2002 will build
with this version without modification.

The POP3 driver will, with new servers that support CAPA, use the LIST
command to get the elt->rfc822_size and the TOP command to get the message
header, instead of fetching the entire message.  Note that it is a bad idea
to do this with old servers, since they may misimplement LIST and TOP.  The
result is a substantial performance improvement.

Subject extraction for comparisons in SORT and THREAD are now done in full
compliance with the rules laid out in the specification.  This only makes
a difference if "re:" was part of a MIME quoted-word.

The new experimental #move namespace allows download-and-delete from a source
mailbox to a destination mailbox.  Immediately following #move is a delimiter
character which must not appear in the source mailbox name, then the source
mailbox name, then the delimiter again, then the destination mailbox name.
For example:
	#move+{pop3.foo.com/pop3}+INBOX
will download messages from "pop3.foo.com" into your local INBOX.

The NNTP driver now uses the LIST EXTENSIONS command as described in the
current NNTP protocol specification draft, and will prefer to use OVER over
XOVER, HDR over XHDR, etc.

The SET_NNTPRANGE function of mail_parameters() can be used to limit the
number of articles recognized by the NNTP driver, resulting in a substantial
performance improvement with NNTP servers that may have hundreds of thousands
of old articles in the spool.  If set non-zero, then only the last n article
numbers will be considered.  If you are on a slow link, you may want to set
this to 1000 or less.

Besides the normally tested UNIX and 32-bit Microsoft platforms, this release
has also been tested and will once build under TOPS-20 and VAX/VMS.  I also
fixed a bug which would keep it from building on 16-bit DOS, but I don't know
if it will build on that platform or not since I no longer have a system with
the old DOS C compiler.  It has not been tested on Macintosh (note however
that Mac OS X is a type of UNIX and should build), Amiga, or OS/2, and probably
no longer builds on those platforms.


Updated: 7 January 2003

imap-2002b is a maintenace release, released concurrently with Pine 4.52,
and contains only bugfixes.  Programs written for imap-2002 will build with
this version without modification.

Drivers which do not announce new mail are now indicated by the DR_NONEWMAIL
driver flag.  Driver which do not announce new mail when read-only are now
indicated by the DR_NONEWMAILRONLY flag.

There are no user-visible functional enhancements in this version.


Updated: 10 December 2002

imap-2002a is a maintenance release, consisting entirely of critical
bugfixes.  Programs written for imap-2002 will build with this version
without modification.

There are no functional enhancements in this version.


Updated: 28 October 2002

imap-2002 is a major release.  Programs written for imap-2001 will probably
build with this version without modification, with one exception.  That
exception is if the program uses [GS]ET_DISABLEAUTOMATICSHAREDNAMESPACES,
which has been renamed to [GS]ET_DISABLEAUTOSHAREDNS in order to placate
some compilers which don't like very long names.

SSLTYPE=nopwd is now the default, in accordance with current IESG security
requirements.  In order to build the IMAP toolkit without SSL/TLS you must
now use SSLTYPE=none.  At initial build time, you will be told if the SSLTYPE
setting is in compliance with IESG security requirements, and if it is not
you will be asked to confirm to continue the build.

ORDEREDSUBJECT threading has been changed in accordance with draft 12 of the
IMAP threading specification.  Previously, each non-root message in an
ORDEREDSUBJECT thread has been a child of the message immediately preceeding
it in the thread.  Draft 12 changes this so that the second message in the
thread is the child of the first (root) message, and all subsequent messages
are siblings of the first message.  This is significant in MUAs which display
the thread structure graphically; the new definition is much saner than the
old one since it does not nest endlessly due to parent/child relationships
that may not exist.  This also impacts imapd, since imapd's THREAD command
will return a thread structure.

RFC 1730 server support, which was disabled in imap-2001, is now fully
removed from imapd.  imapd still supports IMAP2bis, specifically the FIND
command, since there are still a few IMAP2 clients out there.

The IMAP client routines in the c-client library continue to support recognize
RFC 1730 servers, but do not implement the deprecated features of RFC 1730.

The Frequently Asked Questions file is now in HTML format, although a text
version (generated from the HTML version with Lynx) is also provided.

A new program, mailutil, is now bundled with the IMAP toolkit.  mailutil
replaces the old chkmail, imapcopy, imapmove, imapxfer, mbxcopy, mbxcreat,
and mbxcvt programs that were distributed in the imap-utils.  In addition,
the tmail, dmail, and mlock programs from the imap-utils are now also
bundled with the IMAP toolkit.

In addition to the usual bugfixes, the following c-client functionalities
are new in imap-2002:

The SET_DISABLE822TZTEXT parameter allows a client to suppress generation of
the "human friendly" time zone text in RFC822 dates.  This placates netnews
and some broken SMTP servers which think that long timezone names from Windows
are an attempt at a buffer overflow attack.

The restrictBox option in env_unix.c sets "restricted box" functionality,
which disables access to the root (leading "/"), access to other user's
directories (leading "~"), and access to superior directories via "..".

Content-Location is now supported by the "location" member of the BODY
structure.  Note that there is a bug in the IMAP client code in older
versions of the c-client library that causes it to handle BODYSTRUCTURE
extension data improperly if that data is a literal.  The new functionality
for Content-Location may trigger this bug.  The fix is either to upgrade
the IMAP client program to the imap-2002 version of c-client or to remove
the Content-Location support from imapd.

There are now 8 spare bits for application use in both the elts and the
mail streams.

mail_search() now returns a value (previously it was void).  If mail_search()
returns NIL, then the supplied charset was invalid or the IMAP server
returned NO (probably because the supplied charset was invalid).

New utf8_charset() routine to look up a charset and return c-client's
database about that charset if found.  Among other things, this will give
you the scripts supported by that charset and its Unicode conversion table.

New FT_NOLOOKAHEAD flag for mail_fetch_structure() disables fetching of
any envelopes other than the one specified.  Otherwise, it will try to do
anticipatory fetching (up to IMAPLOOKAHEAD).

New GET_FETCHLOOKAHEAD allows better control of mail_fetch_structure()
lookahead.  Instead of looking IMAPLOOKAHEAD messages forward from the
specified message, it will use a supplied SEARCHSET to generate message
sequences and ranges.  It will stop at IMAPLOOKAHEAD messages or at the
completion of a range which exceeds IMAPLOOKAHEAD.  The search set only
applies to the next mail_fetch_structure() on that stream, and is cleared
once it is used.  Call with
  SEARCHSET **set = (SEARCHSET **)
    mail_parameters (stream,GET_FETCHLOOKAHEAD,(void *) stream);
  *set = pointer to desired search set

New mail_shortdate() routine returns an date in the format expected by
SEARCHPGMs.


Updated: 2 November 2001

imap-2001a is a maintenance release, consisting primarily of bugfixes
including some critical bugfixes to crash and denial of service problems.
Programs written for imap-2001 will build with this version without
modification.

The following new facilities have also been added:

The new /norsh switch in mailbox names provides a more intuitive way of
disabling rsh-IMAP than the existing :143 or setting the rsh-timeout to 0.

Passwords are no longer returned in mm_dlog() callbacks unless the
application sets the SET_DEBUGSENSITIVE parameter.

The SET_NETFSSTATBUG parameter allows an application to force the
traditional UNIX mailbox driver to close and reopen the mailbox at ping
time.  This is EXTREMELY inefficient, and should only be used to access
files stored on AFS and old NFS systems.

The ISO 8859 and Windows conversion tables have been updated to comply
with Unicode 3.1, and the KOI8-R table has been verified as compliant with
Unicode 3.1.

The SPECIALS mechanism for passing parameters to the lowest level Makefile
has been updated to be more general.  See the next item for why you might
care.

New lrh port to build on Red Hat Linux 7.2, with pre-set definitions for
the places where Red Hat has placed Kerberos and SSL.  It's actually just
the lnp port with SPECIALS defined accordingly.  You may want to use it as
a model if your system needs such definitions.  Note that SPECIALS is
primarily for IMAP toolkit (and Pine) purposes, and that user settings
should use EXTRASPECIALS instead.


Updated: 22 June 2001

imap-2001 is a major release.  Programs written for imap-2000 will probably
build with this version without modification.

The FAQ document has been significantly expanded.  Be sure to read it for
more information.

In addition to the usual bugfixes, the following features are new in
imap-2001:

SSL is now fully integrated into the IMAP toolkit; the old "alt" kludges to
be able to produce a "sanitized" version of the IMAP toolkit to comply with
late unlamented US export regulations are now completely gone.

Full client and server TLS support is also in this release.

The server certificate must be signed by a trusted certificate authority and
the name in the certificate match the user's entry for the server host name;
this means that the user must enter a fully-qualified host name.

To build with SSL/TLS on UNIX, you now use "SSLTYPE=unix" instead of the
former "SPECIALAUTHENTICATORS=ssl".  To build with SSL/TLS on UNIX and disable
the use of plaintext passwords except when under SSL/TLS, use "SSLTYPE=nopwd"
instead of "SSLTYPE=unix".

RFC 1730 (IMAP4 as opposed to IMAP4rev1) support is turned off by default in
imapd.  No clients should still be using RFC 1730 protocol.  Look at the imapd
Makefile for how to re-enable RFC 1730 support.  Note that this code may be
removed in the future, so if you think you need it you had better let me know.

There are some new options (turned off by default) which attempt to work around
problems in certain clients.  See the FAQ file for more details.


Updated: 24 January 2001

imap-2000c is a maintenance release, consisting primarily of bugfixes.


Updated: 9 January 2001

imap-2000b is a maintenance release, consisting primarily of bugfixes.


Updated: 9 November 2000

imap-2000a is a maintenance release, consisting primarily of bugfixes.


Updated: 19 September 2000

imap-2000 is a major release.  There are major internal and external changes
from earlier versions (imap-4.x and imap-3.x series).  Programs written for
imap-4.x will probably build with this version without modification.  It is
extremely unlikely that a program written for imap-3.x or earlier series will
build with this version without modifications.  Drivers written for earlier
versions will definitely need to be rewritten.

In addition to the usual bugfixes, the following features are new in imap-2000:

SSL support is now available.  For UNIX, it is necessary to install some
version of OpenSSL; see imap-2000/docs/SSLBUILD for more information.  SSL
support is now automatic for the NT, NTK, and W2K ports.  SSL use is indicated
by the /ssl switch in the mailbox name.

With SSL connections, the server certificate is validated by the client code
on UNIX, and Windows 2000 unless /novalidate-cert is specified.  Server
certificates are currently is not validated on Windows 9x, Windows Millenium,
or Windows NT 4; this is an artifact of the operating system and not the port
(e.g. client code using the NT port will validate certificates if running on
Windows 2000).  On UNIX, the server certificate must be signed by a trusted
certificate authority.  On Windows 2000, the certificate must be signed by a
trusted certificate authority and match the user's entry for the server host
name; this means that the user must enter a fully-qualified host name.

Calendar reclama for the benefit of old broken non-Y2K compliant software.
Two digit years from 00 to 69 will be interpreted as 2000 through 2069.  In
addition, three digit years from 100 to 105 will be interpreted as 2000
through 2005.

Support for REFERENCES threading (in addition to the previously-existing
ORDEREDSUBJECT threading).

Support for the IMAP MULTIAPPEND extension.  This allows much faster uploading
of multiple messages to an IMAP server.

Support for the LOGINDISABLED IMAP capability.  If the IMAP server sends
LOGINDISABLED as a capability, the client code will never attempt to send an
IMAP LOGIN command.

Support for SASL authentication identity vs. authorization identity.  If the
authentication method does not support this concept (e.g. AUTH=CRAM-MD5,
AUTH=LOGIN, LOGIN command), the "*" character in the user name may be used to
indicate a separate authentication identity; for example, "fred*joe" indicates
authorization identity "fred", authentication identity "joe".


UNIX-specific Changes:

Support for SASL authentication identity vs. authorization identity in the
IMAP and POP3 servers.  If the user indicated by the authentication identity
is in the "mailadm" group, he may specify any authorization identity and get
logged in as the authorization identity user.

If the IMAP and POP3 servers are build with PASSWDTYPE=nul, it will send
LOGINDISABLED as a capability and also disable the AUTH=LOGIN and AUTH=PLAIN
SASL authenticators.

New MAILSUBDIR build option to change the default mailbox directory from the
user's home directory to a subdirectory of the user's home directory.  See
imap-2000/Makefile for more information.

New CHROOT_SERVER build option for closed server systems only.  If defined, a
chroot() call to the user's home directory is done as part of the login
process.  See imap-2000/Makefile for more information.

New ADVERTISE_THE_WORLD build option which will add an IMAP namespace that
points to the root.  Not for the faint of heart.

UNIX format mailboxes no longer require the pseudo-message, nor will a
pseudo-message be added to a mailbox that does not have one.  A new
X-IMAPbase: header will be written in the first message.  This is rather less
efficient and robust than the pseudo-message (which remains the encouraged
mechanism; UNIX format mailboxes will always be created with it), but perhaps
will pacify some people who get upset by the pseudo-message.

When building with MIT Kerberos it will try to detect and use libk5crypto.a
instead of libcrypto.a.

The mbx driver is more aggressive about cleaning up expunged messages that
couldn't be purged because of shared access to the mailbox at the time of
expunge.  Now, every checkpoint will try to purge such messages; and a
checkpoint is attempted at close time.


Windows-specific Changes:

New W2K port for Windows 2000.  In addition to supporting SSL using the
official SSPI interface (the NT and NTK ports invoke SChannel.DLL directly),
the W2K port also supports Microsoft Kerberos.  Note that the NT and NTK ports
will work on Windows 2000, but the W2K port will not work on NT4, Windows
9x, or Windows Millenium.

There is now a #user namespace, equivalent to the "~" namespace on UNIX.



Changes for Developers:

New c-client.h file which acts as a master include.  c-client based
applications should now include c-client.h instead of the individual c-client
files (mail.h, misc.h, etc.).  It is believed that c-client.h will work in C++
applications.

New GET_FREEENVELOPESPAREP/SET_FREEENVELOPESPAREP and
GET_FREEELTSPAREP/SET_FREEELTSPAREP function callbacks to free the "sparep"
member of the envelope and cache elements, respectively.

New OP_MULNEWSRC flag to mail_open() to use multiple newsrc files, and new
GET_NEWSRCQUERY/SET_NEWSRCQUERY function callbacks to get the name of the
newsrc file for news access.

New "secret" nntp_article() function to do the NNTP ARTICLE command; this is
generally useful only when chasing news URLs.

New GET_HIDEDOTFILES/SET_HIDEDOTFILES feature to suppress file names that
start with "." in mail_list() results.