		       Change History for MHonArc
		       ==========================
		       <http://www.mhonarc.org/>
 ---------------------------------------------------------------------------
|   PLEASE READ RELNOTES FOR CHANGES THAT CAN HAVE COMPATIBILITY IMPACTS    |
|           FOR ARCHIVES CREATED FROM PAST RELEASES OF MHONARC.             |
 ---------------------------------------------------------------------------

    Some change notes are brief; consult the documentation for further
    information/clarification.  It is possible that some changes to
    MHonArc are not documented here, but every effort is made to list
    all visible changes.

YYYY/MM/DD
============================================================================
2012/MM/DD	(2.6.19)

* Security Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    35388   commentized subjects allow PHP code injection
    ------  ------------------------------------------------------------

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    32987   Lots of deprecation warnings with Perl 5.12
    ------  ------------------------------------------------------------

============================================================================
2011/01/09	(2.6.18)

* Update to HTML filter to improve filtering of event-based
  attributes.

============================================================================
2011/01/09	(2.6.17)

* Security Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    32013   CVE-2010-4524: Improper escaping of certain HTML
            sequences (XSS) 
    32014   CVE-2010-1677: DoS when processing html messages with deep
            tag nesting
    32080   Specially crafted <base href> can lead to XSS exploit
    ------  ------------------------------------------------------------

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    13853   Creation of archive with attachments writes over symlinks
    14747   major (10X) memory savings possible in some situations
    15433   relative attachmentdir is relative to current working dir,
            not outdir 
    17660   Threaded index resource ordering doesn't allow well formed
            XML output
    17860   incorrect nested HTML Tags for references
    17904   FieldOrder affects AddressModifyCode
    18113   Inconsistant thread slices w/ poor man's windowing
    18908   X-Subject data get split in separate lines
    20074   extra space in subject
    20142   strip backslash in rfc822 From: field
    23198   Incorrect Setting Installation Directory
    24247   iso2022jp.pl: unneeded ESC ( B remains in message body
    25225   dir_create() fails to make temporary directories (PATCH)
    25486   Resource FieldStore causes .mhonarc.db to grow over bounds
    26577   Changed semantic for unpack breaks UTF-8
    32032   TextEncode related resource information not saved correctly
            in db file
    ------  ------------------------------------------------------------

* Added FOLLOWSYMLINKS resource (Bug #13853).

* When KEEPONRMM is enabled, messages that are removed from
  the archive do not cause linked messages to be updated.  This allows
  for pages that use $TSLICE$ to maintain thread links for messages
  that "fall off" of the maintained list of archived messages.

* Added pre-extraction of From name and From address.  This
  provides a performance improvement for archives that make use of
  the $FROMADDR$ and $FROMADDRNAME$ resource variables along with
  author sorting.

* Added mapping of message index keys to time stamp.  This should
  provide some performance gain since parsing out of time stamp from
  index is no longer required.

* Cache last message number in db to avoid directory scan of archive
  each time an add operation is performed.  This provides a performance
  improvement for large archives and on file systems where directory
  reading with many files may not be optimal.  Thanks go to Christopher
  Lindsey for patch.

* Added References and In-Reply-To to as-is fields list to avoid
  automatic modification of message IDs if address-rewriting is
  in effect.

* Simplified regular expression for detecting addresses.
  New expression performs significantly better than the previous
  expression, but still matches the vast majority of addresses
  used today.

============================================================================
2006/06/09	(2.6.16)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    14704   HTML mail does not get its charset converted (patch
	    included)
    14713   qprint.pl should be able to handle a soft line break at
	    the end of the string
    14813   MIMEFILTERS settings not retained in database
    16368   in urlize change %X to %02X
    ------  ------------------------------------------------------------

============================================================================
2005/07/27	(2.6.15)

* Removed debugging statement introduced during v2.6.14 development
  which caused the filename of each message to be printed to stderr
  when processing MH-style folders.

* Fixed META.yml for CPAN: YAML is picky about tab characters, and
  there was a couple of tab characters causing CPAN's YAML parser to
  abort with an error.

============================================================================
2005/07/23	(2.6.14)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     2641   Additional Callbacks
     3225   CHARSETCONVERTERS not reset across multi-archive process
    11759   email address exposed in subject line
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

* New resources:

    PRINTXCOMMENTS	Print <!--X-...--> comments in generated pages.

* Added "Performance Tips" document: Provides configuration tips
  to improve the execution performance of mhonarc.

============================================================================
2005/07/06	(2.6.13)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    12314   linebreak not utf-8 aware
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

* mha-preview example script changes:

  - If preview data not available for message, the empty string
    is used.  Before, undef was returned to mhonarc, causing
    warning messages and $X-MSG-PREVIEW$ to show up on index pages.

  - Beefed up preview text extraction to skip past quoted text.

  Someday, mha-preview functionality will be intrinisic to mhonarc.

============================================================================
2005/06/08	(2.6.12)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
    11761   spammode causes broken mailto: links in message body
    13316   No warning generated when RCFILE set to non-existent file
    13317   POSIX::setlocale() not invoked with LANG resource setting
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

* New resources:

    MIMEINCS		Content-types to allow.

* Beefed up filtering of UTF-8 messages:  "Malformed UTF-8
  ..." warnings are now suppressed with such sequences being converted
  to U+FFFD (&#xFFFD;), which should normally cause an HTML viewer
  to render a question-mark-like glyph.

  Earlier version passed malformed utf-8 sequences through.
  No bug/security problems have been reported against this, but it
  was a bad practice that has now been corrected.

* The return value for $mhonarc::CBMessageBodyRead and
  $mhonarc::CBRawMessageBodyRead is no longer N/A.  If the return
  value evaluates to false, the current message will be excluded from
  the archive and further processing.  A true value must be returned
  if the message is to not be excluded.

============================================================================
2005/05/20	(2.6.11)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     9050   Regex abort error in mhmimetypes.pl under Win32
    11187   incorrectly parsing UTF-8 encoded messages
    11207   usenameext option to m2h_external::filter has no effect
    11760   spammode false positives on some HTML mail
    11762   rel=nofollow attribute support in message body hyperlinks
    11977   TSLICETOPBEGCUR ignored
    12512   Consecutive spaces not displayed in some cases
    12802   SubjectStripCode not working on message file
    12930   Cross site scripting bug in m2h_text_html::filter
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

============================================================================
2004/05/17	(2.6.10)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     8982   Can't use global $1 in "my" at base64.pl
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

============================================================================
2004/05/07	(2.6.9)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     5473   directory separator for attachments on W2K
     5643   New ressource - newsserver
     5758   MULTIPG and NOSAVERESOURCES cause archive to be rewritten
     5905   Modification of non-creatable array value attempted
     6208   Mhonarc creates slightly incorrect HTML-code
     7571   <include> element doesn't look for resource files in
	    $OUTDIR$
     7628   typo in mhrcfile.pl
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

* New resources:

    ATTACHMENTDIR	Directory to save attachments.
    ATTACHMENTURL	Web URL to attachment directory.
    NEWSURL		URL template for linking to newsgroups.

* Attachment filenames have changed from the numeric-style
  <ext><#####>.<ext> to <ext><XXXXXXXXXX>.<ext> where <XXXXXXXXXX>
  is a random string.  The change corresponds with a change to the
  API to mhonarc::write_attachment() function in mhmimetypes.pl.

* m2h_text_plain::filter:
  . Changed default quoting styles: Left rule changed from 0.1em
    to 0.2em and the color changed from #0000FF to #5555EE.

  . Minor changes to flowed formatting in order to provide
    consistancy with how Mozilla's Gecko engine renders flowed text.

* base64.pl will use MIME::Base64 module if present.  MIME::Base64
  uses an underly C implementation for decoding, so it is noticably
  faster than the pure-Perl approach.

============================================================================
2003/08/12	(2.6.8)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     4719   Spurious read_fmt_file call
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

============================================================================
2003/08/07	(2.6.7)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     4569   Problem with unfolding can mess up boundary processing in
	    multipart messages.
     4594   Initial space on lines removed when using fancyquote.
    ------  ------------------------------------------------------------
    <https://savannah.nongnu.org/bugs/?group=mhonarc>

* Added LANG resource to define locale.  Affects resource filename
  resolution and message subject and author sorting.

* readmail.pl updated to define the following special header field
  keys passed to filter routines:

    x-mha-content-type	  The media type of the entity extracted from
			  content-type entity header
    x-mha-part-number	  The relative part number of the entity with
			  respect to parent entity.  To get the
			  absolute part number, use
			  readmail::get_full_part_number($fields).
    x-mha-parent-header	  Reference to parent header fields hash.

  This, and other data structures, are now mentioned in the MIMEFILTERS
  resource page.

* Text/richtext tag, <samepage>, is quietly dropped in mhtxtenrich.pl.

============================================================================
2003/07/21	(2.6.6)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     4387   m2h_text_plain::filter maxwidth usage can lead to crash
	    with a certain kind of input 
    ------  ------------------------------------------------------------
    <http://savannah.nongnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.6.6&chunksz=50>

============================================================================
2003/07/19	(2.6.5)

* Bug Fixes:

    Bug ID  Summary
    ------  ------------------------------------------------------------
     4126   Typo in mhopt.pl causes error message for big5
	    character set 
     4315   allowcomments' directive to filter() is ignored
    ------  ------------------------------------------------------------
    <http://savannah.nongnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.6.5&chunksz=50>

* An architecture independent RPM package is now provided for
  installation.  Because of this, the package name format has slightly
  changed to be consistent RPM, and other, package managers:

      Old format      New Format
      -------------   -------------
      MHonArcX.X.X    MHonArc-X.X.X

  Installation document has been updated to reflect this change.

  If you create third-party distribution bundles for MHonArc, you may
  need to update your bundling process to take account of this change,
  mainly because the directory created when extracting the tar or
  zip bundles now include the hyphen.

============================================================================
2003/06/20	(2.6.4)

* Bug Fixes:

  + Official:

      Bug ID  Summary
      ------  ------------------------------------------------------------
      3478    Quoted-Printable decoding should also work with     
	      lowercase hex numbers                               
      ------  ------------------------------------------------------------
      <http://savannah.nongnu.org/bugs/index.php?group_id=1968
       &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
       &fix_release=2.6.4&chunksz=50>

  + Unoffical:

      - It appears that the UTF8 mapping table for cp1252,
	MHonArc::UTF8::CP1252, had bad data.  This has been
	fixed.

* Management of character mapping tables have been changed.  The
  various .pm module tables are now auto-generated by ucm, and
  similiar, map files.  For the end-user, the change should be
  transparent.  The change only affects how developers maintain
  the tables, and the change should make it much easier to make
  fixes to any mappings.

============================================================================
2003/04/05	(2.6.3)

* Bug Fixes:

    Bug ID  Summary
    ------  --------------------------------------------------------------
    3020    Trailing \ in regex
    3128    XSS Vulnerabilies
    2971    spammode option interferes with iso-2022-jp
    ------  --------------------------------------------------------------
  <http://savannah.nongnu.org/bugs/index.php?group_id=1968
   &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
   &fix_release=2.6.3&chunksz=50>

============================================================================
2003/03/11	(2.6.2)

* Bug Fixes:

  Bug   Resolution Fixed       Summary                                   
  ID               Release                                               
  2738  Fixed      2.6.2       An illegal From: address can cause MHonArc
			       to hang                                   

  <http://savannah.nongnu.org/bugs/index.php?group_id=1968
   &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
   &fix_release=2.6.2&chunksz=50>

============================================================================
2003/02/22	(2.6.1)

* Bug Fixes: See
    <http://savannah.nongnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.6.1&chunksz=50>

* Corrected character mapping tables for VISCII based on a
  message to the perl-unicode mailing list.

* Added FASTTEMPFILES resource which causes MHonArc to use
  non-random temporary files.  This is less secure, but provides
  a little bit of speed improvement.

============================================================================
2003/02/10	(2.6.0)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.6.0&chunksz=50>

* New resources:

    DEFCHARSET		Default character set of message text data.
    CHARSETALIASES	Define aliases for base charset names.
    DBFILEPERMS		File permissions for DBFILE.
    FIELDSTORE		Message header fields to store in database.
    FILEPERMS		File permissions for archive files.
    ICONURLPREFIX	URL string to prepend to ICONS URLs.
    MODIFYBODYADDRESSES	Apply ADDRESSMODIFYCODE to text message bodies.
    RECONVERT		Reconvert existing messages.
    TENDBUTTON		Button to last message in thread.
    TENDBUTTONIA	Inactive button to last message in thread.
    TENDLINKIA		Inactive link to last message in thread.
    TENDLINK		Link to last message in thread.
    TEXTENCODE		Encode message text to given character encoding.
    TTOPBUTTON		Button to first message in thread.
    TTOPBUTTONIA	Inactive button to first message in thread.
    TTOPLINKIA		Inactive link to first message in thread.
    TTOPLINK		Link to first message in thread.

* New resource variables:

    $ICONURLPREFIX$	Value of ICONURLPREFIX resource.
    $MSGHFIELD$		Retrieve header field value stored via
			FIELDSTORE.

* MHonArc::CharEnt:
  + Several charset mappings added to MHonArc::CharEnt with the
    default value for CHARSETCONVERTERS updated to reflect the new
    mappings.  New charset supported include UTF-8, various Cyrillic
    sets, VISCII, Chinese sets, Japanese (iso-2022-jp and euc-jp),
    Korean, Apple-based charsets, etc.  See the documentation for
    the CHARSETCONVERTERS and CHARSETALIASES for complete list of
    character sets supported.

    Note: Sets that have bidirectional rendering (Hebrew, Arabic)
    exist, but automatic directional re-ording for rendering is
    currently not supported.

  . Some existing mappings have been updated to use Unicode numeric
    character entity references (&#xHHHH;) instead of standard SGML
    character entity references (eg. &Aelig;).  Most, if not all,
    web browsers only support the set of SGML entity references
    defined in the HTML 4.0 specification.

    All existing tables should now generate entity references
    recognized by all HTML 4.0 compliant browsers.

* MHonArc::UTF8:
  . Module completely redone to support various versions of Perl.
    utf8 support code added to all conversion to utf8 with perl
    installations that do not have utf8 support, but to also
    leverage perl installations with utf8-related modules.

* Default filter for iso-8859-1 and iso-2022-jp changed to
  MHonArc::CharEnt::str2sgml.  This helps keep MHonArc locale
  neutral in its default configuration.  Special note added
  to release notes for Japanese users about the change.
  
* m2h_text_plain::filter (mhtxtplain.pl):
  + Added more robust handling of format=flowed data.  By default,
    all text is rendered in a monospaced font to provide visual
    consistency between flowed and fixed text.  Proportional spaced
    font can be generated using the "nonfixed" option (where
    "keepspace" option should also be used to help preserve the
    formatting characteristics of the data).

  + Added "fancyquote" option to provide highlight of quoted text
    similiar to text/plain;format=flowed data.

  + Added "disableflowed" option to disable the flowed data
    conversion.  Data will be converted as regular text/plain.
    This option is useful for archives that cater to text-based
    browsers.

  + Added "quoteclass=<classname>" option to specify a CSS classname
    to assign to BLOCKQUOTE elements added when processing flowed
    data or when "fancyquote" is active.  This suppresses inline
    style generation.

  + Added "subdir" option for use when "uudecode" is enabled.

  - Reduced set of quote characters to just '>'.  Other characters
    are used by some people (eg. '}', '|', '+'), especially on the
    USENET, but supporting them tends to produce undesirable
    results, especially when using fancyquote.
    (Maybe make it configurable?)

  + If uudecode and usename specified, check if file ends in
    .s?html?, and if so, pass data to HTML filter.

  . Make sure to return a non-empty string for an empty body
    when in uudecode mode.  Avoids bogus warning message that
    data could not be converted.

* MIMEEXCS automatically handles unofficial version of a media type.
  For example:

    <MIMEEXCS>
    text/html
    </MIMEEXCS>

  Will exclude text/html and text/x-html data.

* m2h_text_html::filter (mhtxthtml.pl):
  + CHARSETCONVERTERS is used for converting character data.
  
  - Removed default=charset option.  This option is no longer
    needed with new character encoding processing features and
    CHARSETALIASES resource.

  + Convert javascript:... URLs to "_javascript_:..." when scripting
    is disabled (the default).  This is an extra measure ontop of
    element and attribute stripping.

  * <a href>'s are now preserved when cid: only URLs enabled (the
    default).  This prevents regular hyperlinks in HTML messages from
    getting stripped, which I think most people desire.  Otherwise,
    the allownoncidurls option must be used, and then this opens one
    up to potential XSS attacks.

    Due to the javascript: URL munging, preserving <a href>'s should
    be safe from auto-XSS attacks.  Readers should still be careful
    about any links they activate.

  + Added "subdir" option to specify that MHTML referenced data
    (e.g. images) are saved in a subdirectory.

  + Added "disablerelated" to disable cid: URL resolution.

  . STYLE and CLASS attributes stripped if nofont argument specified.

* m2h_text_enriched::filter (mhtxtenrich.pl):
  + CHARSETCONVERTERS is used for converting character data.
  + <lang><param>lang</param> is now mapped to <dir lang="lang">.
  + Added handling of some text/richtext tags.
  . Escape unrecognized tags.

* Archive file creation modified to minimize the local symlink exploits:

  1.  A temp file with a random name is first created and written to.
  2.  Temp file is compressed if GZIPFILES is active.
  3.  Temp file is renamed to final filename.
  4.  File permissions are set according to FILEPERMS/DBFILEPERMS.

  Using a random temp filename makes it difficult for someone to
  predict filenames to execute a symlink exploit.  The rename operation
  is immune to symlink exploits, hence trying to using well-known names
  (e.g. maillist.html, threads.html) for exploitation will not work.

  A similiar technique is used for directory creation for filters
  that support the "subdir" option.

  Generation of temp files is done via the File::Temp module, if
  installed.  If not installed, a homegrown implementation is used.
  Although not as secure and robust as File::Temp, it's better than
  nothing and should provide a decent deterrent.

* Setuid/setgid execution causes mhonarc to terminate with an error.
  Mhonarc does not pass taint checks, so we abort with an error that
  setuid/setgid execution is not supported.  MHonArc is too insecure
  for setuid operation and trying to make it setuid-safe would require
  alot of work and potentially limit a large amount of functionality.

* More robust parsing used for determining $FROMNAME$ and $FROMADDR*$
  resource variables.

* rfc822.pl library removed and replaced with MHonArc::RFC822 module.

* Warning message, "Unable to process data..." removed from message
  page when unable to convert any part of a message (usually due to
  user-defined MIMEFILTERS settings).  Instead, a warning message
  is generated to standard error (like other mhonarc warnings) and
  the resulting message page will have a blank message body.

* m2h_msg_extbody::filter: (mhmsgextbody.pl)
  + Added support for http/x-http access type.  This appears to
    be an experimental access type since the general URI type can be
    used instead.
  . Properly sanitize parameter data.
  . Some minor cosmetic changes in the HTML generated.

* m2h_text_tsv::filter (mhtxttsv.pl):
  . Sanitize field data.

* m2h_text_setext::filter (mhtxtsetext.pl) has been removed.  It
  appears this media-type is part of document history.

============================================================================
2002/12/21	(2.5.14)

* Security patch release: This release fixes a cross-site scripting
  (XSS) vulnerability in m2h_text_html::filter (the HTML filter).
  A specially crafted HTML message can have scripting markup get
  by the script filtering done by m2h_text_html::filter.

============================================================================
2002/10/21	(2.5.13)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.13&chunksz=50>

* DBFILE resource can now be set to an absolute pathname.  This
  allows the database file to be located in a separate location than
  in the archive directory.  If not an absolute pathname, then
  value is treated relative to OUTDIR.

* readmail.pl updated to handle MHTML messages better.  mhtxthtml.pl
  changed accordingly.

* readmail.pl handling of malformed multipart messages improved.
  Cases were a the terminating boundary delimiter did not exist would
  generate a warning message in the converted message body that data
  could not be converted.  This case should now be handled so that
  end of entitiy implies a terminating boundary delimiter,
  (Thanks goto Randy Blaustein for providing real-world test cases).

* Fixed problem where some message attachments were "lost".  This
  mainly occurs when using mha-decode with the -dcd-digest option,
  or if you have registered the m2h_external::filter for message/*
  data types.
  (Thanks goto Steve Johnson for finding this problem.)

* m2h_external::filter will now include the subject of a message
  in the attachment link if saving message/* data to a file.

* m2h_external::filter properly escapes the filename parameter
  when displaying it in the attachment link.  This is done to
  avoid any possible XSS exploits.  Note, no exploits have been
  reported by using the filename parameter in messages, so this
  change is more of a preemptive measure.

* m2h_external::filter will fall back to a "txt" extension for
  unknown text types instead of a "bin" extension.

* m2h_text_plain::filter: Removed hardcoded 'as-is' for US-ASCII
  data.  This is so a user could define a converter if having to deal
  with mislabeled character data.
  (Thanks goto Mooffie for finally finding a real-world case to not
  hardcode us-ascii).

============================================================================
2002/09/03	(2.5.12)

* Strip more tags and attributes that could potentially be used for
  XSS exploits in the HTML filter.  This is a more of a preemptive
  change since no new exploits have been reported.

* DATEFIELDS resource now supports indexed field names.  For example:

    <DateFields>
    received[1]:received[0]:date
    </DateFields>

  The example says that mhonarc should check the second received
  field, then the first received field, and then the first date field
  to determine the date of a message.

============================================================================
2002/08/03	(2.5.11)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.11&chunksz=50>

* Applied Takashi P.KATOH's patch for iso_2022_jp::clip function
  to support $has_tag flag as defined by TEXTCLIPFUNC resource.

* The following mail header fields added to list of fields that can
  contain mail addresses: mail-reply-to, original-bcc, original-cc,
  original-from, original-sender, original-to, resent-bcc, x-envelope.
  Applicable to MAILTO, MAILTOURL, and ADDRESSMODIFYCODE resources.

* Added documentation for TEXTCLIPFUNC resource.  Forgot to add it
  for v2.5.10 release.

============================================================================
2002/07/28	(2.5.10)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.10&chunksz=50>

* Added TEXTCLIPFUNC resource: Defines the text clipping function
  that should be used by MHonArc.  This function is mainly used
  in resource variable expansion where clipping has been specified,
  for example, "$SUBJECT:72$".

* Added clip() function in MHonArc::UTF8 that can be registed via
  TEXTCLIPFUNC resource to handling clipping of UTF-8 text.

* Example utf-8.mrc updated to include some corrections and to
  define TEXTCLIPFUNC resource.

* Improved navigation links to resource reference pages which should
  help their usability.

============================================================================
2002/07/19	(2.5.9)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.9&chunksz=50>

* Added MHonArc::UTF8 CHARSETCONVERTER module as recommended at
  <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=131512&repeatmerged=yes>.
  However, module redone to use utf8 pragma in Perl where appropriate
  and to remove unnecessary code.  Use of module does require that
  the Unicode::MapUTF8 module is installed and the utf8 pragma is
  supported in the version of Perl you are using.

  A example resource file, "utf-8.mrc", has been added to the
  resource file example appendix section on how UTF-8 output can
  be done in MHonArc.

  NOTE: The MHonArc core is still not UTF-8-aware, so some text
	processing may not work as expected on UTF-8 data.
	Possible problem points:

	. Auto-URL hyperlinking in text/plain messages in
	  mhtxtplain.pl.
	. Auto-message-id detection in messages.
	. Resource variable text clipping.

	There may be others, but in general, if there is a problem,
	it should be uncommon and should not affect the overall
	functionality of MHonArc.  Problems can be avoided by
	not using, or disabling, various resources.

* mhtxtplain.pl:
  . Removed exception case of iso-2022-jp character data since it
    does not allow alternative iso-2022-jp character set conversion
    functions via CHARSETCONVERTERS.

    NOTE: This does eliminate the smart handling of URL detection
	  for the variable-width character set.  Hence, the URL
	  detection could technically match non-URLs, or munge
	  a character at URL boundaries, but it is unknown on how
	  likely this is.  If it is a problem, the "nourl" argument
	  should be specified to this filter.

    NOTE: The old-style "smart" URL functionality can be re-enabled by
	  writing a custom CHARSETCONVERTER for iso-2022-jp that
	  just calls iso_2022_jp::jp2022_to_html in iso2022jp.pl.

  . Minor modification to flowed text/plain formatting that hopefully
    makes quoted text look better than before.

* FAQ changes:
  + Added, "Does MHonArc support Unicode?"
  * Changed, "Can MHonArc create non-English archives?"
  + Added, "Can MHonArc process Evolution folders?"

============================================================================
2002/06/28	(2.5.8)

* Added MIMEALTPREFS resource: Content-type preferences for
  multipart/alternative data.  You can now tell MHonArc to use the
  text/plain part over a text/html part in multipart/alternative
  messages.

* Added the following resources:

    IDXPGSSMARKUP   Markup at the beginning of all index pages.
    MSGPGSSMARKUP   Markup at the beginning of all message pages.
    TIDXPGSSMARKUP  Markup at the beginning of all thread index pages.

  Each resource will default to the value of the SSMARKUP resource
  if not defined.

* Removed <DBFILE> resource element since it useless since an archive
  database is read before any resource files are parsed.  The proper
  way to specify an alternative DBFILE is via the -dbfile command-line
  option or the M2H_DBFILE envariable.

* Release notes updated about upgrading from v2.1.x, or earlier archive.
  Running a later version is safe, but all MIME-related resources will
  be reset to default values.  For v2.5.8, and later, the MIMEARGS
  setting will preserved.

* Removed references to HEADER and FOOTER resources in the docs.
  Resources removed in v2.5.0.

* Updated default resource layout settings in docs to use lowercase
  tag names since MHonArc changed to use lowercase in defaults
  in v2.4.7.

* FAQ updates:
    . Mention MIMEALTPREFS.
    . Added MIMEARGS examples in MIME section.

============================================================================
2002/06/21	(2.5.7)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.7&chunksz=50>

* Updated docs to reflect address change of users' mailing list:
  mhonarc@ncsa.uiuc.edu -> mhonarc-users@mhonarc.org.

* Some minor FAQ changes, mainly mentioning mharc as a possible
  solution to some questions.

============================================================================
2002/06/18	(2.5.6)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.6&chunksz=50>

* Added NOSUBJECTTXT resource: Defines raw subject text to use
  for messages that do not have a subject.

============================================================================
2002/05/28	(2.5.5)

* Bug Fixes: See
    <http://savannah.gnu.org/bugs/index.php?group_id=1968
     &set=custom&advsrch=0&msort=0&report_id=105&go_report=Go
     &fix_release=2.5.5&chunksz=50>

* Incorporated format=flowed support into mhtxtplain.pl contributed
  by Ken Hirsch, with some minor improvements.

* MODTIME resource is set to off if setting modification date on files
  is not supported for given platform.  A warning message will be
  generated.

* Added mha-preview program in examples/: A front-end program to
  MHonArc that provides support for the resource variable
  $X-MSG-PREVIEW$ that expands to first part of a message body.
  This program illustrated the usage of the callback API.

  NOTE: It is probable that support for message preview text
	may become a supported feature within the standard mhonarc
	program.  There are no guarantees that when implemented,
	it will be compatible with how mha-preview does it.

* Added blog.mrc in examples/: A resource file that generates
  a page containing the content of all messages.  This example
  is also listed in the resource file examples appendix.

* Some documentation updates and enhancements.

============================================================================
2002/05/03	(2.5.4)

* Added more API callback functions:

    $CBDbPreLoad
	Right before database file is loaded.
    $CBDbPreSave
	Right before database file is written.
    $CBDbSave
	When data has been written.
    $CBRawMessageBodyRead
	After message body is read from input
    $CBRcVarExpand
	When a resource variable is being expanded.

  See API appendix of the documentation for more information.

* mha-decode now supports the following option: -dcd-digest.  This
  tells mha-decode to not recursively process attached message/rfc822
  and message/news entities.  This option is useful to extract
  out all the individual messages of a message digest.

* Added message/rfc822 and message/news to mhmimetypes.pl
  content-type => extension/description hash.  The extension used
  is ".822".

* Added ISO-8859-15 to default value of CHARSETCONVERTERS.  This should
  have been done in the previous release.

* A readmail:: variable is not written to database file if it is
  the default value.  The readmail:: variables that can be saved
  are controled by the CHARSETCONVERTERS, MIMEFILTERS, and MIMEARGS
  resources.

============================================================================
2002/04/18	(2.5.3)

*   Added 'use locale' pragmas to be applied when sorting messages.
    This is considered experimental, but it appears to give better
    results when sorting text that contains 8-bit-non-English
    characters.  This is far from any real locale support, but
    hopefully it is better than nothing.

*   Beefed up HTML filtering in mhtxthtml.pl to eliminate some
    security exploits.

    CAUTION: If you are worried about security, it is recommended
	     that you disable support of text/html messages in
	     your mail archives.  There is no guarantee that
	     the mhtxthtml.pl library is robust enough to
	     eliminate all possible exploits that can occur with
	     HTML data.

    Thanks goto Jason Molenda and Hiromitsu Takagi for spotting
    more exploit cases.

*   mhtxtplain.pl checks MIMEXCS if text/html data is excluded
    when the htmlcheck option is specified.  Seems unnecessary
    because someone use excludes HTML data will probably not use
    the htmlcheck option to m2h_text_plain::filter.

*   Modified mail address extraction for $FROMADDR$ resource
    variable to help deal with malformed From: header fields.
    Thanks to Eugene Eric Kim for the recommendation.

*   Fixed uudecoding support in mhtxtplain.pl to handle spaces
    in filenames and \r\n EOLs.  Thanks to Jordan Russell for
    spotting this.

*   Added ISO-8859-15 mappings.  Thanks goto Jan Kraeber for the
    contribution.

*   Removed GIF images from distribution.  All GIF images
    have been converted to PNG format.  Transparency of PNG
    images may only be supported in the latest versions of various
    graphical web browsers.

    See <http://www.gnu.org/philosophy/gif.html> for reasons
    why GIF images should not be used.

*   Source code imported into CVS.  CVS respository is currently
    not available publicly.  Stilling wondering if a site like
    savannah.gnu.org should be used or if the respository should
    be hosted independently, like at www.mhonarc.org.

*   Fixed regex patterns in readmail.pl to avoid Perl warning
    messages.

*   Created a contrib/ directory to contain any contributed
    programs imported into the MHonArc distribution.  Moved
    prsfrom.pl from extras/ to contrib/.

*   Added Security section to FAQ.  Provided more information to
    question, "Why does a message get split into mulitple messages
    with no headers?", mainly information contributed by users.

============================================================================
2001/11/24	(2.5.2)

    o	mha-dbrecover new options:

	  -dbr-startnum # 
	      The starting message number to recover data from. This
	      option is useful if you have many message files in a
	      directory, but you only want to recover a subset of the
	      files. If this option is not specified, the starting
	      number is 0.

	  -dbr-endnum # 
	      The ending message number to recover data from. This
	      option is useful if you have many message files in a
	      directory, but you only want to recover a subset of the
	      files. If this option is not specified, all messages
	      starting from -dbr-startnum will be recovered.

    o	MSGPGBEGIN default value changed where $SUBJECTNA:72$ has
	been replaced with $SUBJECTNA$.  This is so default values
	do not have any possible conflicts with variable-width
	character sets.

============================================================================
2001/11/13	(2.5.1)

    o	Added special note within the release notes about
	downgrading.

    o	Some documentation corrections.

============================================================================
2001/10/14	(2.5.0)

    [This is non-beta release of 2.5.0.  See the change notes
     below and for the various beta release for a complete list of
     changes from the last v2.4 release.]

    o	The ICONS resource has been updated to support the association
	of icons at the base type level (e.g. text/*) and to specify
	width and height hints.  The example icon resource file
	listed in an appendix of the documentation updated to
	to use changes to ICONS resource.

    o	Formatting of attachment links within the m2hexternal.pl
	filter has been updated to provide more verbose information.
	Description of the format provided in the MIMEFILTERS
	documentation.	Also, a 'frame' filter argument is now
	supported to instruct the filter to draw a frame around
	the link.

    o   Default value for MIMEArgs has been changed to the following:

	  <MIMEArgs>
	  m2h_external::filter; inline
	  </MIMEArgs>

	This is more concise then previous default value.

	On a resource file maintenance standpoint, it is generally
	best to specify filter arguments at the filter level and
	not at the content-type level.

    o   Value of Perl's $^O variable printed with version information
	for -V, -v, -help command-line options.

    o	The count of new messages added to archive are now printed
	along with the total message count when QUIET is not active.

============================================================================
2001/09/05	(2.5.0b2)

    o	Long overdue update of ACKNOWLG file.

    o	New resources:

	  TSLICELEVELS	-- Maximum depth for thread slices.

    o	New resource variables:

	  $TLEVEL$	-- Numeric level of message in thread.

    o	Added recognition of windows-1250 and windows-1252 charsets
	into MHonArc::CharEnt and to default value of CHARSETCONVERTERS
	resource.  To apply to existing archives, use mha-dbedit
	with examples/def-mime.mrc resource file.

    o	SUBJECTREPLYRXP now used to determine if "Re: " is added
	when $SUBJECT$ is used within MAILTOURL.

    o	Code cleanup to eliminate perl -w warnings.  Cleanup not
	required for running MHonArc, but convenient for those that
	use MHonArc with perl's -w option.

============================================================================
2001/08/26	(2.5.0b)

    o	API for MIMEFILTERS has been changed.  Content filters are
	now called as follows:

	  ($html, @files) =
	      &filter($fields_hash_ref, $body_data_ref, $is_decoded,
		      $filter_args);

	Paramaters:
	  $fields_hash_ref
		      A reference to hash of message/part header
		      fields.  Keys are field names in lowercase
		      and values are array references containing the
		      field values.  For example, to obtain the
		      content-type, if defined, you would do:

			$fields_hash_ref->{'content-type'}[0]

		      Values for a fields are stored in arrays since
		      duplication of fields are possible.  For example,
		      the Received: header field is typically repeated
		      multiple times.  For fields that only occur once,
		      then array for the field will only contain one
		      item.

	  $body_data_ref
		      Reference to body data.  It is okay for the
		      filter to modify the text in-place.

	  $is_decoded
		      Boolean flag if body data has been decoded.
		      This is normally true unless some non-standard
		      content-transfer-encoding is used.

	  $filter_args
		      String containing filter args as defined by
		      MIMEARGS resource.

	Return:
	  The return value is still treated in the same manner as
	  previous releases.  The first item in the return list is
	  the text that should printed to the message page.  Any
	  other items in the return list are derived filenames created
	  by the filter.  If undef, or the empty string, is returned,
	  readmail.pl assumes the filter was unable to filter the
	  data.

	All the filters provided in the MHonArc distribution have
	been modified to use the new calling convention.

    o	The HEADER and FOOTER resources are no longer supported.

    o	The default value of DEFRCNAME is now ".mhonarc.mrc"
	("mhonarc.mrc" for Win/DOS).

    o	ISO8859 character set data processing now defaults to using
	the MHonArc::CharEnt module.  The old iso8859.pl library
	is still provided for compatibility with older archives.
	To update archives to use the new settings, you can run
	the following command,

	    mha-dbedit -rcfile examples/def-mime.mrc \
		       -outdir /path/to/archive

	where "examples/def-mime.mrc" represents the default MIME
	processing resources for MHonArc provided within the MHonArc
	distribution.

	The new module is more efficient in memory usage by only
	loading mappings for character sets actually processed.  The
	old iso8859.pl library preloads all mappings.  Also, the
	module is designed to be easily extensible for processing
	any 8-bit-based character sets.

    o	Reference, follow-up, and derived file information of a
	message is now stored in a different format in the database
	(and internally).  MHonArc will auto-update older archives
	to the new format.  The newer format should provide some
	performance improvement.

    o	Messages with no subjects are now stored with no subjects.
	In previous releases, the text "No Subject" was automatically
	added as a message was parsed, hence there was no real
	indicator that a message had no real subject.

	A related change is that messages without subject text
	are skipped in subject-based thread detection.  Therefore,
	a no-subject message will never be a possible follow-up,
	but it is still possible for it to be an explicit follow-up
	if it includes reference message-ids.

	NOTE: This functionality does not apply to messages
	processed by earlier versions where the text "No Subject"
	was auto-applied to messages when parsed.  A recreation
	of an archive from the original message data would
	have to be done to have new behavior applied to message
	processed by earlier releases.

	A messages with no subject will now have the string
	"[no subject]" displayed any time the $SUBJECT$ resource
	variable is used for the message.

    o	New resources:

	    FIRSTPGLINK 	Link markup for first page of main index.
	    LASTPGLINK 		Link markup for last page of main index.
	    TFIRSTPGLINK 	Link markup for first page of thread index.
	    TLASTPGLINK 	Link markup for last page of thread index.
	    TNEXTINBUTTON	Button markup for next message
				within a thread.
	    TNEXTINBUTTONIA	Inactive button markup for next
				message within a thread.
	    TNEXTINLINK 	Link markup for next message within
				a thread.
	    TNEXTINLINKIA	Inactive link markup for next
				message within a thread.
	    TNEXTTOPBUTTON	Button markup for first message in
				the next thread.
	    TNEXTTOPBUTTONIA	Inactive button markup for first
				message in the next thread.
	    TPREVINBUTTON	Button markup for previous message
				within a thread.
	    TPREVINBUTTONIA	Inactive button markup for previous
				message within a thread.
	    TPREVINLINK 	Link markup for previous message
				within a thread.
	    TPREVINLINKIA	Inactive link markup for previous
				message within a thread.
	    TPREVTOPBUTTON	Button markup for first message in the
				previous thread.
	    TPREVTOPBUTTONIA	Inactive button markup for first
				message in the previous thread.
	    TSLICECONTBEGIN	Thread slice markup before the
				continuation of a broken thread.
	    TSLICECONTEND	Thread slice markup after the
				continuation of a broken thread.
	    TSLICEINDENTBEGIN	Thread slice markup for opening a level
				when continuing a broken thread.
	    TSLICEINDENTEND	Thread slice markup for closing a level
				when continuing a broken thread.
	    TSLICELIEND 	Ending markup for a thread slice
				message listing.
	    TSLICELIENDCUR	Ending markup for a thread slice
				message listing.
	    TSLICELINONE	Thread slice markup for a missing
				message in thread slice.
	    TSLICELINONEEND	Ending markup for a missing message in
				thread slice.
	    TSLICELITXT 	Markup for a thread slice message
				listing.
	    TSLICELITXTCUR	Markup for a thread slice message
				listing if current message.
	    TSLICESINGLETXT	Markup for a thread slice listing with
				no follow-ups.
	    TSLICESINGLETXTCUR	Markup for a thread slice listing with
				no follow-ups if current message.
	    TSLICESUBJECTBEG	Markup before a subject based thread
				slice listing.
	    TSLICESUBJECTEND	Markup after a subject based thread
				slice listing.
	    TSLICESUBLISTBEG	Thread slice markup for starting a
				sub-thread.
	    TSLICESUBLISTEND	Thread slice markup for ending a
				sub-thread.
	    TSLICETOPBEGIN	Thread slice markup for the root/start
				of a thread.
	    TSLICETOPBEGINCUR	Thread slice markup for the root/start
				of a thread.
	    TSLICETOPEND	Thread slice markup for the end of a
				thread.
	    TSLICETOPENDCUR	Thread slice markup for the end of a
				thread if current message.

    o	$TSLICE$ resource variable can now take up to three arguments:

	    $TSLICE(<before>;<after>;<inclusive>)$

	where,

	    <before>	: Number indicated the maximum number of
			  message to print before the current message.
			  If empty, the before value specified in
			  TSLICE resource will be used.
	    <after>	: Number indicated the maximum number of
			  message to print after the current message.
			  If empty, the after value specified in
			  TSLICE resource will be used.
	    <inclusive> : If `1', only messages within the current
			  thread will be printed.  If `0', messages
			  from the previous and next threads can
			  be printed if the values for <before> and
			  <after> would go beyond the current thread.

    o	TSLICE resource updated to allow specification of default
	value of inclusive flag.

    o	The following new message specifications can be used for
	message data-related resource variables:

	    TNEXTIN		Next message within current thread.
	    TNEXTTOP		Start of next thread.
	    TPREVIN		Next message within current thread.
	    TPREVTOP		Start of previous thread.

	When used as arguments to the the $BUTTON$ and $LINK$ resource
	variables, the TNEXTINBUTTON(IA), TNEXTTOPBUTTON(IA),
	TPREVINBUTTON(IA), TPREVTOPBUTTON(IA), TNEXTINLINK(IA),
	TNEXTTOPLINK(IA), TPREVINLINK(IA), TPREVTOPLINK(IA) resources
	are respectively applied.

    o	The use of TNEXT, TPREV (and new TNEXTTOP and TPREVTOP)
	message specifications in resource variables behave more
	intuitively when TREVERSE is active.  If at the boundaries
	of a thread, TNEXT and TPREV will reference the first
	message of the next thread by date and the first message
	of the previous thread by date, respectively.

    o	Version of MHonArc and Perl are printed when MHonArc starts
	unless QUIET is active.

    o	mhtxtplain.pl (text/plain) filter changes:

	.   If the htmlcheck option is set and it is detected that
	    the data is HTML, an attempt is first made to use the
	    registered text/html filter via MIMEFILTERS.  If none
	    is defined, mhtxthtml.pl will be used.

	.   When uudecode option is set, an attempt is to use
	    the registered decoder for uuencode via MIMEDECODERS.
	    If not defined, then base64::uudecode is used from
	    base64.pl.

    o	mhtxthtml.pl (text/html) filter changes:

	.   Elements that have URL attributes that auto-load data --
	    IMG, BODY, IFRAME, FRAME, OBJECT, SCRIPT, INPUT -- have the
	    atributes converted to 'javascript:void(0);' URLs.	See new
	    'allownoncidurls' filter argument below for more details.

	.   The follow filter arguments have been added:

	    allownoncidurls Preserve URL-based attributes that are not
			    cid: URLs.	Normally, any URL-based
			    attribute -- href, src, background,
			    classid, data, longdesc -- will be
			    converted to 'javascript:void(0);'
			    if it is not a cid: URL.  This is to
			    prevent malicious URLs that verify mail
			    addresses for spam purposes, secretly set
			    cookies, or gather some statistical data
			    automatically with the use of elements
			    that cause browsers to automatically
			    fetch data: IMG, BODY, IFRAME, FRAME,
			    OBJECT, SCRIPT, INPUT.

	    notitle  	    Do not print title.

    o	Searching for OTHERINDEXES resource files has been modified.
	The following lists the search order for an OTHERINDEXES
	resource file:

	    1. Current working directory.
	    2. Same directory that the first resource file was read as
	       specified by the RCFILE resource.
	    3. User's home directory.
	    4. Archive directory.
	    5. Perl's @INC.

    o	FIRST, LAST, TFIRST, and TLAST idx_page_spec arguments to
	$PGLINK$ are now supported via the FIRSTPGLINK, LASTPGLINK,
	TFIRSTPGLINK, and TLASTPGLINK resources.

    o	$PGLINKLIST$ resource variable changed to print entire
	list of page links if no arguments are provided.  To get
	the entire list for thread indexes, use: $PGLINKLIST(T)$.

    o	Date parsing routine updated to recognize dates in the
	following format: Weekday, Month DD, YYYY HH:MM Zone.
	Apparently, this is useful if converting mail saved to
	a file in text format from MS Outlook.

    o	Support for defining Perl function callbacks when a
	new message header is read and just after a message body
	has been converted.  Documentation about the callbacks is
	provided in a new API appendix section in the documentation
	and is provided in comments in the example mhasiteinit.pl
	provided in the examples/ directory.

    o	Various internal changes have been made to try to eradicate
	Perl 4-based conventions.  For example, the use of typeglobs to
	pass by "reference" has been replaced by using real references.

	Assuming nothing was screwed up, this change should be
	transparent to most users (with the notable exception of the
	API changes to MIMEFILTERS registered routines).  However,
	if you have mucked with MHonArc internals, or created custom
	modifications, you may need to be aware that changes have
	been made.

============================================================================
2001/06/10	(2.4.9)

    o	Added the following resources:

	    MIMEEXCS		List of content-types to exclude
				from processing.  Exclusion occurs
				before data is passed to filters.

    o	mhtxtplain.pl: If decoding uuencoded data, the data will
	be excluded if application/octet-stream is listed the
	MIMEEXCS resource.

    o	mhtxthtml.pl: If a CID URL is not available, the CID URL
	is no longer preserved in the converted output.  The CID
	URL is stripped.

    o	Added the following to mhmimetypes.pl content-type table:

	  application/ms-excel		=> xls:MS-Excel spreadsheet
	  application/ms-powerpoint	=> ppt:MS-Powerpoint presentation
	  application/ms-project	=> mpp:MS-Project file

	The "vnd." official versions are already present, but
	some application use the above.

    o	TODO list added to distribution.

=======================================================================
2001/04/13	(2.4.8)

    o	Added the following resources:

	    KEEPONRMM   	Do not remove message files from disk
				when messages are removed from the
				archive.

    o	m2h_text_plain::filter now uses CHARSETCONVERTERS for
	translating text data with a specified charset parameter.
	The only exception is iso-2022-jp, which is handled directly
	to properly support nourl flag.

    o	m2h_external::filter new arguments:

	excludeexts=ext1,...
		  A comma separated list of message specified filename
		  extensions to exclude.  I.e.	If the filename
		  extension matches an extension in excludeexts, the
		  content will not be written.	The return markup
		  will contain the name of the attachment, but no
		  link to the data.  This option is best used with
		  application/octet-stream to exclude unwanted data
		  that is not tagged with the proper content-type.
		  The m2h_null::filter can be used to exclude content
		  by content-type.

    o	m2h_null::filter will now output a one line description
	of the excluded content.  This is so the reader knows that
	there was message content not saved within the archive.

    o	m2h_text_plain::filter new arguments:

	usename		If extracting uuencoded data, the filename
			specified should be used.

    o	m2h_text_html::filter new arguments:

 	allowcomments	Preserve any comment declarations.  Normally
 			Comment declarations are munged to prevent
 			SSI attacks or comments that can conflict
 			with MHonArc processing.  Use this option
 			with care.

	(NOTE: Comment declarations were completely stripped before,
	 but the regex used was known to crash perl on large comment
	 declarations, so a simplier expression is now used to
	 modify comment declarations to prevent possible attacks.)

=======================================================================
2000/10/28	(2.4.7)

    o	Added the following options to m2h_text_plain::filter:

	attachcheck	Honor attachment disposition.  By default,
			all text/plain data is displayed inline on
			the message page.  If attachcheck is specified
			and Content-Disposition specifies the data as
			an attachment, the data is saved to a file
			with a link to it from the message page.
	htmlcheck	Check if message is actually an HTML message
			(to get around abhorrent MUAs).  The message
			is treated as HTML if the first non-whitespace
			data looks like the start of an HTML document.

    o	FROMFIELD resource default value is now:

	  from:mail-reply-to:reply-to:return-path:apparently-from:
	  sender:resent-sender

	The change is the addition of "mail-reply-to."

    o	Added the following resource variables:

	    $MSGTORDNUM$	Ordinal number of message in current
				thread.

    o	Added the following resource variable message specificiers:

	    TEND		Last message of current discussion
				thread.
	    TTOP		Top/root message of current discussion
				thread.

    o	Changes to readmail.pl:
	-   %Cid hash keys are now URLs.  Content-Ids are denoted
	    as "cid:..."  Hash also contains Content-Location values
	    of message parts.  This allows filters (like the HTML
	    filter) to check for external URL references where
	    the data for the reference is included with the message.
	-   More robust handling of malformed multipart messages.

    o	The null filter is applied to application/ms-tnef by default.

    o	Lowercase tag names are now used in default resource values
	that contain HTML markup.

    o	Bug fixes to the documentation.

=======================================================================
2000/04/24	(2.4.6)

    o	Stricter check is made when decoded quoted-printable data.
	An escape sequence is only converted to a raw character if
	a it is a valid escape sequence.  I.e.  Any '=' not followed
	by two hexadecimal characters is left as-is.

    o	Call to Digest::MD5::md5_hex() wrapped in eval block in
	case of bad installations of Digest::MD5 module.

=======================================================================
2000/02/14	(2.4.5)

    o	Following changes to m2h_text_html::filter:
	-   All comment declarations are removed.  This avoid
	    potential SSI attacks and declarations that may conflict
	    with MHonArc.
	-   Additional tags have been added to the to-strip list
	    to avoid potential client-side scripting attacks.  See
	    MIMEFILTERS docs for list.
	-   Added "nofont" option to strip out any <font> tags.

    o	Added application/x-bzip2 to known mime types (mhmimetypes.pl).

    o	Simple modification to get_time_from_date() in mhutil.pl to
	handle abhorrent case of message date using a 2 digit year.

    o	Under VMS, the default lock file name has been changed to
	"mhonarc_lck" for directory based locking will work.

    o	mhonarc::htmlize/entify now translates the double-quote
	character (") to &quot;.

    o	Added VARREGEX resource to allow customization of resource
	variable matching.  Mainly for use with resource files written
	on multibyte charsets like SJIS.  Use with caution.

=======================================================================
1999/10/01	(2.4.4)

    o	Added the following resources:
    
	    MIMEDECODERS	Content-Transfer-Encoding decoding
				functions.

    o	Added the following resource variables:

	    $PGLINKLIST$	Print out a list of index page links.

    o	New content filter for message/external-body.

    o	Message/delivery-status content handled by mhtxtplain.pl

    o	Support for "Zone[+-]DDDD" timezone specification.

    o	MAILparse_parameter_str() function added to readmail.pl.
	Function supports parsing parameter value strings with support
	for RFC 2184 extensions.  Function added to provide
	support for message/external-body filter.

=======================================================================
1999/08/15	(2.4.3)

    o	Added the following resources:

	    POSIXSTRFTIME	Use POSIX::strftime() or not for
				processing time format strings

    o	The "latin[1-6]" character sets defined in the default
	value of CHARSETCONVERTERS.   iso8859::str2sgml modified
	to use proper iso8859 map for specified latin[1-6]
	specification.

    o	The text/html filter now strips out scripting markup by
	default.  To allow scripting markup to be preserved, the
	"allowscript" option can be used.

    o	Unknown media-types are now treated as application/octet-stream,
	which will invoke the application/octet-stream filter.
	Because of this, an explicit entry for application/octet-stream
	has been added to the default value of MIMEFILTERS.

    o	If in a multipart/alternative entity, and no known media-types
	exists, the last part is treated as application/octet-stream.

=======================================================================
1999/08/11	(2.4.2)

    o	Added the following resources:

	    STDIN		Source for standard input

    o	Added the following resource variables:

	    $ENV$		Print an environment variable

    o	Added support for decoding uuencoded data within text
	messages in mhtxtplain.pl.  Decoding activated via the
	"uudecode" option.

    o	For processing time format strings, POSIX::strftime() is
	used, if available.  If not, MHonArc implementation is
	used.

    o	The default value of FROMFIELDS now includes "return-path".

    o	Description section moved before Options section in -help
	message.

=======================================================================
1999/07/25	(2.4.1)

    o	Added the following resources:

	    MSGEXCFILTER	Perl expressions for excluding
				messages from archive.
	    SAVERESOURCES	Flag if resource values should be
				saved in database.

    o	Added the following resource variables:

	    $HTMLEXT$		Value of HTMLEXT resource.

    o	Documentation corrections an additions.

    o	Use of typeglobs removed from mhdb.pl.

    o	mhtime.pl explicitly defined in mhonarc package.

=======================================================================
1999/06/25	(2.4.0)

    o	Added the following resources:

	    ADDRESSMODIFYCODE	Perl expressions to apply to addresses
				during message header conversion.
	    CHECKNOARCHIVE	Check "no archive" flag in messages.
	    LOCKMETHOD		The type of archive locking performed.
	    SPAMMODE		Perform actions to deter email address
				harvesters.
	    SSMARKUP		Markup at the *very* beginning of any
				generated page.
	    STDOUT		Destination of stdout messages/data.
	    STDERR		Destination of stderr messages/data.
	    SUBJECTTHREADS	To check, or not to check, subjects when
				computing threads.

    o	Added the following resource variables:

	    $FROMADDRNAME$	Username portion of From email address.
	    $FROMADDRDOMAIN$	Domain portion of From email address.
	    $TOADDRNAME$	Username portion of an email address
				(applicable in MAILTOURL only).
	    $TOADDRDOMAIN$	Domain portion of an email address
				(applicable in MAILTOURL only).

    o	A new utility program: mha-decode.  The program functions
	as a MIME message decoder.  Can be used against mail folders
	or single messages.

    o	The "PARENT" argument to applicable resource variables is now
	called "TPARENT".  This change should not affect anyone since
	the "PARENT" argument did not work properly in previous
	releases.

    o	SUBJECTHEADER and HEADBODYSEP resource changes will now affect
	existing messages that are edited during normal operations or
	via EDITIDX.  Note, messages created from old versions of
	MHonArc may not be affected.

    o	The default TIMEZONES settings now has a more complete list.

    o	Timezone acronym settings now support [+-]HHMM specifications.

    o	Support for ISO-2022-JP encoded strings in message headers
	is now supported.  It does assume that HTML viewer supports
	ISO-2022-JP.

    o	If Digest::MD5 is installed, md5_hex() will be used to create
	message-ids for messages without message-ids.  This allows
	MHonArc to ignore non-message-id archived messages in ADD mode.
	The MD5 digest is computed only on message header for efficieny.
	If Digest::MD5 is not installed, a message-id will still be
	assigned if none present, but MHonArc will not be able to
	detect if message has already been archived in subsequent ADD
	operations.

    o	Text/html filter supports the "noscript" option.  If
	specified, any script-related markup will be removed.
	This provides added security to avoid sites being compromised
	with foreign client-side scripting.

    o	Added the following options to mhexternal.pl (the save-to-file
	filter): forceattach, forceinline, and inlineexts.

    o	Recognize mailing list headers as defined by RFC 2369 and
	hyperlink URLs listed.

    o	If no boundaries exist in a multipart message (even though
	a boundary is defined in the header), MHonArc will treat
	the entire body as the first part.  This prevents "unable
	to process" warnings.

    o	The "<!--X-From" comment declaration at the top of converted
	messages is now munged by a modified ROT13 to facilitate
	anti-spam-bot measures, but still provide the "From"
	information for mha-dbrecover.

    o	When editing message pages, the new version of the page is now
	created as a temporary file and then if successfully created,
	it will get renamed to its proper name.  This help avoids "losing"
	a message page if there is an error during page editing.  The
	same method is applied to the dumping of DBFILE.

    o	Message sorting modified to improve sorting performance when
	sorting by subject and author.

    o	URL matching expression in mhtxtplain.pl modified to handle
	'&' characters.

=======================================================================
1998/11/08	(2.3.3)

    Bug Fixes

=======================================================================
1998/11/01	(2.3.2)

    o	A new (improved) install.me program to do the installation.
	See INSTALL for more information.

=======================================================================
1998/10/25	(2.3.1)

    Please read the RELNOTES file for important information regarding
    upgrading to v2.2.x, or later, from pre-v2.2 releases.

    o	Support for MHTML.  I.e.  An HTML document that references data
	included as other parts to the mail message, will be converted
	so the data will be shown where referenced.  Before, all
	referenced data was shown at the end of the message.

    o	Auto-computing the name for attachments no longer caches
	data, so performance may decrease when processing MIME
	messages.  This change is required since multiple filters can
	now write data to files and not all to the same directory (a
	common utility function now exists for writing data to a file).
	Also, it avoids behavioral problems with custom front-ends
	that operate on multiple archives in a single process.

    o	Changes to readmail.pl inorder to support MHTML.  Changes
	done should help the handling of other multipart/related
	data types.

=======================================================================
1998/10/10	(2.3.0)

    o	Perl 5 is now required to run MHonArc.  Although the code
	base is still "Perl 4-style", many changes made use of Perl 5
	constructs.

    o	New utility programs added to the dustribution:

	    mha-dbedit		- Make resource/db changes w/o touching
				  pages.
	    mha-dbrecover	- Rebuild database from HTML message
				  files.

    o	Many resource variables have been changed to take arguments
	to control what values the variables will expand to.  Because,
	of this, many variables are now deprecated.  However, old
	forms of resource variables are still recognized.

	See the documentation for more information on resource
	variables (a new section on resource variables has been
	added to the documentation) and the newer syntax.

    o	New resources:

	    AFS			- Skip archive directory permission check
	    ANNOTATE		- Annotate message(s).
	    LOCK		- To lock, or not to lock.
	    MSGPGS		- Print, or not, message pages.
	    NOTE		- Annotate markup.
	    NOTEIA		- Inactive annotate markup.
	    NOTEDIR		- Directory where annotations are located.
	    NOTETEXT		- Annotation text.
	    PAGENUM		- Page to output when using GENIDX with
				  MULTIPG.
	    READDB		- Just load the database
				  (useful for application front-ends).
	    USELOCALTIME	- Use localtime to determine day groups in
				  date index listing.

    o	New resource variables:

	    $DDMMYYYY$		- Day/Mon/Year(4 digit)
	    $MMDDYYYY$		- Mon/Day/Year(4 digit)
	    $MSG$		- Filename of message page
	    $SORTTYPE$		- Type of sort in use for main index
	    $TSORTTYPE$		- Type of sort in use for thread index
	    $YYYYMMDD$		- Year(4 digit)/Mon/Day

	Note, many other variables have been changed.  See docs for
	more information.

    o	Added "J" modifier for resource variables.  When specified,
	escapes quote characters so expanded values can be used
	within JavaScript strings.

    o	Added "usenameext" option to mhexternal.pl filter.  When
	specified, mhexternal.pl will use the filename specified in
	the message for determining the filename extension to use.

    o	The -rcfile option can be specified multiple times.  Resource
	files specified are read in the order specified.

    o	The -definevars options has been deprecated in favor of
	-definevar (no ending 's').  -definevar can be specified
	multiple times on the command-line.  The usaage of it is
	exactly the same as -definevars.  The -definevars is still
	supported for backwards compatibility.

    o	The -perlinc option can be specified multiple times.

    o	For the mhtxtplain.pl filter, the TARGET attribute for links is
	now specified only if the target option is specified.

    o	MHonArc is now smarter when the RMM resource is used.  MHonArc
	will now only update pages that are required when messages
	are removed instead of doing a force update on all pages.
	RMM operations will now perform much faster.

    o	Subject based replies are *no longer* treated as a separate
	"group" when printing thread index pages.  I.e.  Subject based
	replies no longer cause a separate TSUBLISTBEG and TSUBLISTEND
	to be invoked.	Before, it was a problem if the HTML OL
	element was used.  OL numbering would restart when subject
	based replies were printed.

    o	GENIDX now supports the use of MULTIPG (w/IDXSIZE).

    o	MHonArc uses rename instead of file copying when editing
	pages.  Should provide a speed increase when editing archive
	pages.

    o	Reason when a file cannot be opened or created is printed
	($! is now included in the error message).

    o	If unable to lock an archive (and -force not specified),
	MHonArc will now return an exit status of 75 (EX_TEMPFAIL).
	This is for the benefit of MTAs (like sendmail) where
	MHonArc is called via an alias.

    o	Some changes to code to make it suitable for MHonArc to be
	embedded into other Perl programs.  The most significant
	changes was to make it possible to process more than one
	archive in a single process instance (note, archives can
	only be processed in sequence and not in parallel).  Now it
	easier to write different application front-ends to MHonArc.

    o	Some other code cleanup in the hopes to improve performance.

=======================================================================
1998/03/03	(2.2.0)

	o  New resource

		MSGIDLINK	  - Hyperlink markup for message-ids
		SUBJECTARTICLERXP - Regex to match articles (a,an,the)
				    in subject text.
		SUBJECTREPLYRXP	  - Regex to match reply annotation
				    in subject text.
		TSLICE		  - Set the size of a thread slice listing
		TSLICEBEG	  - Begin markup of a thread slice listing
		TSLICEEND	  - End markup of a thread slice listing

	o  New resource variables

		$TSLICE$	  - Print thread listing slice relative to
				    current message.

	o  Added default=charset option to mhtxtplain.pl filter.

	o  Added mhtxttsv.pl to handle text/tab-separated-values
	   content.

	o  Expanded list of recognized content-types in mhexternal.pl.

	o  Changed loading of decoders, charset convertes, and
	   content-type filters to be done on demand.  Should
	   provide an increase in start-up time.

	o  Modified source so no Perl structures are in the "main"
	   package.  The base package is now "mhonarc".  This
	   should make it easier for incorporating mhonarc into
	   another Perl program.

	   *IMPORTANT*: This change causes changes to db file format.
	   See release notes on how to upgrade pre v2.2 archives.

	o  Main routines are now located in mhamain.pl.  The main
	   mhonarc source file now just requires mhamain.pl and
	   just calls two main functions.

	o  Although code should still be Perl 4 compatible, Perl
	   related resource documentation now puts preference to
	   Perl 5 notations (eg: MIMEFILTERS, CHARSETCONVERTERS).

=======================================================================
1998/02/23	(2.1.2)

	o  Added the following resources:

		ARCHIVE   	Create archive files
		FROMFIELDS	Define fields to extract "FROM"
		USINGLASTPG	Is $LASTPG$ in use

	o  Removed (almost) all uses of $& in code.  Still used
	   in readmail.pl for decoding non-ASCII encoded text.

	o  Changed the default value of CHARSETCONVERTS resource.
	   The plain, us-ascii, and iso-8859-1 charsets now
	   default to main::htmlize.  This provided a significant
	   performance improvement when process a large amount of
	   input.

	o  Moved thread related routines into a file called
	   mhthread.pl.

	o  MIMEFILTERS, MIMEARGS, and CHARSETCONVERTS resources
	   support Perl 5 package qualification in function names
	   if a semi-colon is used instead of a colon as the
	   list values separator.

	o  Probably some other changes I forgot about.

=======================================================================
1998/02/18	(2.1.1)

	o  Added DATEFIELDS resource.  The resource allows the user to
	   specify the fields (and order) that are checked when
	   MHonArc extracts the date of a message.

	o  RMM can now take message number ranges and/or message-ids.

	o  Added $FROMADDR$ variable for MAILTOURL resource.

	o  Message-id printed in warning about unable to parse date.
	   Helps users locate offending message.

	o  'No Author' used if no message sender is not present.

=======================================================================
1997/06/09	(2.1.0)

	o  Added the following resources:

		DEFRCNAME	Base name of default resource file
		FOLUPBEGIN	Begin markup for message follow-ups
		FOLUPEND	End markup for message follow-ups
		FOLUPLITXT	Markup for follow-up list entry
		GZIPEXE		Pathname of gzip executable
		GZIPFILES	Gzip files
		GZIPLINKS	Add ".gz" to filenames in URLs
		HTMLEXT		HTML extension for files
		MSGBODYEND	Markup at end of converted message body
		MSGPREFIX	Prefix for message filenames
		REFSBEGIN	Begin markup for message references
		REFSEND 	End markup for message references
		REFSLITXT	Markup for reference list entry
		TSORT		Sort threads by date or message number
		TSUBSORT	Sort threads by subject

	o  Changes to mhexternal.pl filter:
	
	    -  Two new options: useicons and iconurl="url".
	    -  Added some more content-types to CTExt hash.

	o  Added filter for text/enriched data (mhtxtenrich.pl).

	o  Changed default setting for MIMEFILTERS.  The following
	   was added:

	    model/*:m2h_external'filter:mhexternal.pl
	    text/enriched:m2h_text_enriched'filter:mhtxtenrich.pl
	    text/richtext:m2h_text_enriched'filter:mhtxtenrich.pl

	o  Some code moved to new library files (mhopt.pl,
	   mhfile.pl).

=======================================================================
1997/05/23	(2.0.1)

    Bug Fixes

=======================================================================
1997/05/16	(2.0.0)

	o  Added TCONTBEGIN, TCONTEND, TINDENTBEGIN, TINDENTEND
	   resources.  They are provided to support the formatting
	   of threads that split across multiple pages of a
	   multipage index.

	o  Added "nonfixed", "maxwidth", and "keepspace" options
	   to text/plain (mhtxtplain.pl) filter.

	o  A directory file is now used for performing archive
	   locking.  This should provide better portability across
	   operating systems.

	o  Dervied files returned from filters can be directories.
	   If so, the any directory is completely removed if the
	   message is removed.

	o  The mhexternal.pl filter can now output files into
	   a subdirectory with the "subdir" option.  This may be
	   useful for those wanting to use the "usename" option
	   and avoid potential filename conflicts.

	o  The $NEXT...$ and $PREV...$ resource variables now
	   behave as one may expect.  I.e.  The are always relative
	   to the base sort method: date, author, subject, message
	   number.  The REVERSE resource has no effect on their
	   values.  Therefore, the variables no longer refer to
	   the actual physical listing order.  This new behavior
	   no longer requires a users to redefine button and link
	   resources for the sake of specifying REVERSE.

	o  "Resent-To" and "Resent-Cc" will now have e-mail
	   address hyperlinked.

	o  Unknown types processed by mhexternal.pl now default
	   to have a ".bin" extension.  This should cause HTTP
	   servers to treat the file as application/octet-stream.

	o  Standard input can be specified as the source of a
	   mailbox by using a lone "-" on the command-line.  Note:
	   You may need to specify "--" first to shut-off option
	   processing so the "-" is not interpreted as the start
	   of an option.

=======================================================================
1997/02/28	(2.0.0 beta 3)

	o  Removed bogus call to output_db() when GENIDX is active.
	   The routine is not loaded when GENIDX is active and the
	   call causes Perl to abort.

	o  Duplicates of the OTHERINDEXES resource should no longer
	   occur.  Before, if the OTHERINDEXES resource gets set
	   during invocation, mhonarc would store duplicate values,
	   causing unnecessary work to be performed.

	o  Fixed problem with blank indexes being created for
	   OTHERINDEXES.  Apparently, there is a bug in Perl, and
	   a work-around fix has been done.

	o  Fixed bug where an extra TSUBLISTEND could get generated.

=======================================================================
1997/02/17	(2.0.0 beta 2)

	o  Added <nosubsort> element and -nosubsort option.

	o  Changed M2H_DATEFMT envariable to M2H_GMTDATEFMT.

	o  Documented LOCKTRIES and LOCKDELAY resources.

	o  New resources:

		AUTHORBEGIN	- Markup for start of author group
		AUTHOREND	- Markup for end of author group
		AUTHSORT	- Sort messages by author
		DAYBEGIN	- Markup for start of day group
		DAYEND  	- Markup for end of day group
		IDXLABEL	- Label for main index
		MSGGMTDATEFMT	- Format of $MSGGMTDATE$
		MSGLOCALDATEFMT	- Format of $MSGLOCALDATE$
		SUBJECTBEGIN	- Markup for start of subject group
		SUBJECTEND	- Markup for end of subject group
		TIDXLABEL	- Label for thread index

	o  New resource variables
		
		$IDXLABEL$	- Label for main index
		$MSGGMTDATE$	- Date of message in GMT format
		$MSGLOCALDATE$	- Date of message in local format
		$TIDXLABEL$	- Label for thread index

	o  Some enhancements to the documentation.

	o  Some code changes.

=======================================================================
1997/01/31	(2.0.0 beta 1)

	o  RFC 1522 support.  Charset filters can be plugged in to
	   handle character sets not recognized by mhonarc.
	   The library, iso8859.pl, contains charset filters for
	   character sets iso-8859-[1-10].

	o  Multi-page index generation.

	o  Subject-based threading is done inconjunction with explicit
	   threading.

	o  Missing messages in a thread are recognized when processing
	   messages that utilize the References field.

	o  New resources for customizing thread indexes.  There is
	   now complete user control on how thread indexes are
	   formatted.

	o  Resource are available to access the next and previous messages
	   in thread from messages.

	o  Inclusion of files containing resource settings can be
	   done within a resource file.

	o  Support for a default resource file.  The default resource
	   file is one of the following, in the order of precedence:

		1. File specified by the M2H_DEFRCFILE envariable
		2. $HOME/.mhonarc.rc
		3. <Install-Library-Dir>/.mhonarc.rc

	   "<Install-Library-Dir>" is the path of the MHonArc library
	   directory defined during installation.  For MS-DOS, replace
	   ".mhonarc.rc" with "MHONARC.RC".

	o  Support for user defined resource variables.

	o  Support for user defined derived files for messages.

	o  Support for the Content-Length field.

	o  Modification time of messages, and derived files, can be
	   set to the Received/Date time specified in the message.

	o  More control on how mail headers get formatted.

	o  Added filter in mhexternal.pl to be the default filter
	   for main content-types: application, image, video, audio.

	o  List of enhancements to mhexternal.pl:
	
		- Show content-type if the data is not recognized.
		- New `ext' filter option to define the extension to
		  use for the created file.
		- New `type' filter option to define the "english"
		  type name of the create file.
		- Content-Disposition is supported.  Filenames are
		  ignored still unless `usename' argument passed to
		  filter.
		- Added recognition of few more content-types

	o  Updated date parsing to figure out the date of a message to be
	   more robust on how it parses a date.  If unable to parse
	   date, the message will take on the current time for sorting
	   purposes.  Also, character case is ignored in month and weekday
	   names.

	o  The comment declaration "<!--X-Body-of-Message-->" is
	   now inserted between the message header and body.  Helps
	   in the building of some search indexes to restrict searches
	   on message data.

	o  Many resource settings are no longer stored in database if
	   the resource is the default value.  Save some disk space and
	   allows resources to self adjust when a dependent resource is
	   changed.

	o  The text/plain filter in mhtxtplain.pl has the following
	   enhancements:
	   
	       -  Check for charset to control character conversion.
	       -  Integrated iso-2022-jp filter (keys off charset)
	       -  Filter option "quote" cause quoted text in message
		  to be italicized.
	       -  Filter option "asis" defines a list of charsets to
		  not convert to sgml entitites.  Example usage:

			asis=iso-8859-1:iso-8859-2

	o  mhtxt2022.pl has been removed since the code has been
	   integrated into mhtxtplain.pl.

	o  Resource file elements that have textual content (ie. no
	   line oriented content) can specify the "chop" attribute
	   to have the last end-of-line stripped from the content.
	   Example usage:

		<nextbuttonia chop>
		[Next]
		</nextbuttonia>

	o  Fixed bug in creating links of message-ids.  Mhonarc blindingly
	   made links of message-ids when editting messages w/o
	   consideration that the message-ids may already be linked.  This
	   caused markup like the following to occur:

	    <A HREF="..."><A HREF="..."><A HREF="...">...</A></A></A>...

	   Browsers handle the invalid markup with no problems, causing
	   the bug to go unnoticed for a long time.  Now, only new
	   added message-ids are scanned for when creating links.

	o  $readmail'FieldSep should now be used instead of $FieldSep
	   for separating duplicate fields in a parsed message header.

	o  The -scan output now prints a 4 digit year.

	o  Bogus space no longer appears in subjects and dates.

	o  Outdir permissions are not checked if -single specified.

	o  Some internal changes to how data is stored in databases
	   (needed for 1522 support).  v2.0 will automatically
	   modify 1.x databases to the 2.0 format.

	o  The -single option utilizes the same mail output routine
	   utilized by regular archive processing.

	o  MhonArc will now handle numbers with leading zeros when
	   the -rmm option is specified.

	o  New resources:

		CHARSETCONVERTERS
				- Specify character set filters
		CONLEN		- Honor content-lengths
		DECODEHEADS	- Decode 1522 encoded data, set for decode
				  only, as message headers are read (see
				  note below)
		DEFINEVAR	- Define resource variables
		DEFINEDERIVED	- Define user defined derived file
		EXPIREDATE	- Message cut-off date
		EXPIREAGE	- Time in seconds from current if msg expires
		FIELDSBEG	- Begin markup of converted mail header
		FIELDSEND	- End markup of converted mail header
		FLDBEG		- Begin markup of mail header field text
		FLDEND		- End markup of mail header field text
		FOLREFS		- Print links to explicit follow-ups & refs
		GMTDATEFMT	- Format of $GMTDATE$
		HEADBODYSEP	- Markup between converted mail header & body
		IDXPREFIX	- Prefix for multi-page main index filenames
		INCLUDE		- Read resources from other files
		LABELBEG	- Begin markup of mail header label
		LABELEND	- End markup of mail header label
		LOCALDATEFMT	- Format of $LOCALDATE$
		MAIN   		- Create main index
		MHPATTERN	- Expression for mesg files in a directory
		MODTIME		- Set file times to message dates
		MONTHS		- Full month names: EOL or ':' separated
		MONTHSABR	- Abbrieviated month names: EOL or ':'
				  separated
		MULTIPG		- Create multi-page indexes
		NEXTPGLINK	- Link to next page in main index
		NEXTPGLINK	- Inactive link to next page in main index
		NOCONLEN	- Ignore content-lengths
		NODECODEHEADS	- Leave message headers "as is" when read
				  (see note below)
		NOFOLREFS	- Do not print links to follow-ups & refs
		NOMAIN 		- Do not create main index
		NOMODTIME	- Do not set file times to message dates
		NOMULTIPG	- Do not create multi-page indexes
		PREVPGLINK	- Link to previous page in main index
		PREVPGLINKIA	- Inactive link to previous page in main index
		SUBJECTHEADER	- Markup for subject header in converted mail
		TIDXPREFIX	- Prefix for multi-page thread index filenames
		TSUBLISTBEG	- List begin in sub-thread
		TSUBLISTEND	- List end in sub-thread
		TSUBJECTBEG	- Begin markup for subject-based sub-thread
		TSUBJECTEND	- End markup for subject-based sub-thread
		TSINGLETXT	- Markup for mesg not part of a thread
		TTOPBEGIN	- Begin for top of a thread
		TTOPEND		- End for a thread
		TLINONE		- Markup for missing message in a thread
		TLIEND		- Thread idx list item end
		TNEXTBUTTON	- Thread next button template
		TNEXTBUTTONIA	- Inactive thread next button template
		TNEXTLINK	- Thread next link template
		TNEXTLINKIA	- Inactive thread next link template
		TNEXTPGLINK	- Link to next page in thread index
		TNEXTPGLINKIA	- Inactive link to next page in thread index
		TPREVBUTTON	- Thread previous button template
		TPREVBUTTONIA	- Inactive thread previous button template
		TPREVLINK	- Thread previous link template
		TPREVLINKIA	- Inactive thread previous link template
		TPREVPGLINK	- Link to prev page in thread index
		TPREVPGLINKIA	- Inactive link to prev page in thread index
		WEEKDAYS	- Full weekday names: EOL or ':' separated
		WEEKDAYSABR	- Abbrieviated weekday names: EOL or ':'
				  separated


	   NOTE
	       1522 processing is done when creating HTML output and
	       the (relevant) data stored in the database stays in
	       encoded form.  The DECODEHEADS resource can be set
	       to decode decode-only charsets when message headers
	       are read.  Hence, the decode-only charsets will be
	       stored in decoded form.	Regular 1522 processing is
	       still done to still-encoded data when generating output.
	       The default is NODECODEHEADS.

	o  List of removed resources:

		NOTSUBSORT, TSUBSORT

	o  New resource variables:
	   (NOTE: Some variables are only valid in certain contexts)

		$FIRSTPG$	- Filename of first page of main index
		$IDXPREFIX$	- Prefix to main index pages' filenames
		$LASTPG$	- Filename of last page of main index
		$NEXTPG$	- Filename of next main index page
		$NEXTPGLINK$	- Link to next page of main index
		$NUMOFPAGES$	- Total number of pages in index
		$PAGENUM$	- Current page number of index
		$PREVPG$	- Filename of previous main index page
		$PREVPGLINK$	- Link to previous page of main index
		$TFIRSTPG$	- Filename of first page of thread index
		$TIDXPREFIX$	- Prefix to thread index pages' filenames
		$TLASTPG$	- Filename of last page of thread index
		$TNEXTBUTTON$	- Button for next mesg in thread
		$TNEXTFROM$	- From of next mesg in thread
		$TNEXTFROMADDR$	- From address of next mesg in thread
		$TNEXTFROMNAME$	- From name of next mesg in thread
		$TNEXTLINK$	- Link for next mesg in thread
		$TNEXTMSG$	- Next mesg filename in thread
		$TNEXTMSGNUM$	- Next mesg number in thread
		$TNEXTPG$	- Filename of next thread index page
		$TNEXTPGLINK$	- Link to next page of thread index
		$TNEXTSUBJECT$	- Next mesg subject in thread
		$TPREVBUTTON$	- Button for prev mesg in thread
		$TPREVFROM$	- From of previous mesg in thread
		$TPREVFROMADDR$	- From address of previous mesg in thread
		$TPREVFROMNAME$	- From name of previous mesg in thread
		$TPREVLINK$	- Link for prev mesg in thread
		$TPREVMSG$	- Previous mesg filename in thread
		$TPREVMSGNUM$	- Previous mesg number in thread
		$TPREVPG$	- Filename of previous thread index page
		$TPREVPGLINK$	- Link to previous page of thread index
		$TPREVSUBJECT$	- Previous mesg subject in thread

	o  Removed resources:

		NOTSUBSORT, TSUBSORT

	o  Some changes to default resource settings.

	o  Reorganized code.  Some new libraries have been created
	   to help in maintenance.

	o  Source code has been put under SCCS revision control.

=======================================================================
1996/07/12	(1.2.3)

	o  Extracted initialization of data structures into mhinit.pl.
	   The file is just required from the main source.

	o  Use q{} instead of qq{} when trying to read database file.
	   Should fix require problem under MS-DOS.

	o  Added <!--X-Reference-Id: ... --> comments at beginning
	   of messages.  May aid in database recovery techniques.

	o  ';'s are now deleted in filenames in mhexternal.pl
	   (applicable only when "usename" option specified)

	o  Added recognition of '/' when converted e-mail addresses
	   to mailto links in message headers.

	o  Simple fix to mhtxt2022.pl for execution under Perl 5.

=======================================================================
1996/04/18	(1.2.2)

	o  Increased the speed performance of base64 decoding.  Speed
	   increase is much greater under Perl 4 than Perl 5.

	o  Added -time option to print out total CPU execution time.
	   Mainly used for debugging reasons (like checking on
	   base64 decoding times).  Time information is sent to
	   standard error.

	o  Added M2H_LOCKDELAY envariable and -lockdelay option.
	   Either can be used to adjust the sleep time between
	   attempts to lock the archive.

	o  Added -force option to override a lock on an archive if
	   attempts to lock fail.

	o  Added image/x-bmp and image/x-pcx to the default supported
	   MIME types.

	o  Ignore "Sv:" at the beginning of subjects when sorting by
	   subject.  "Sv:" is Danish for "Re:".

	o  Fixed bug in mhutil.pl where TIDXPGEND actually set
	   TIDXPGBEG.

	o  Dynamically define exclude_field routine after reading
	   user options.  exclude_field is utilized when formatting
	   a message header in HTML.  Defining the routine at run-time
	   helps reduce the regular expression overhead the old version
	   of the routine entailed.  There should be an increase in
	   overall execution time.

=======================================================================
1996/03/22	(1.2.1)

	o  Added support for x-uuencode content-transfer-encoding.

	o  Added -locktries command-line option.

	o  Added the resource variable $OUTDIR$.

	o  mhexternal.pl filter will use the name parameter string
	   on the content-type field as the anchor text to the file
	   if there is no content-description.

	o  application/x-patch is recognized and processed by the
	   text/plain filter (mhtxtplain.pl).

	o  Fixed bug in install.me and osinit.pl where setting
	   $'PROG caused perl to terminate if $'DIRSEP was a backslash
	   (occured under MS-DOS usage).

	o  Fixed bug in install.me in the create_dir routine.
	   If $DIRSEP was a backslash, the regular expression setting
	   @a would cause perl to abort with an error.

	o  Fixed database bug where the MIMEARGS resource setting
	   was not being stored.

	o  Fixed index listing bug where a reverse listing was not
	   correct if an index size was specified less than the
	   current size of the archive.

=======================================================================
1996/03/01	(1.2.0)

	o  Rewrote message parser routine so it will work under Perl 5
	   for multipart messages.  The rewrite also allows some
	   additional features that are mentioned below.

	o  The -mbox and -mh options are no longer required.  MHonArc
	   will automatically determine which mode to operate in
	   based upon the file arguments.  Hence, one can specify
	   MH folders and mailbox files on the same command-line.
	   Both options are ignored if specified.

	o  An HTML index of an archive contents can be generated to
	   standard output (-genidx).

	o  Message header lines not conforming to RFC 822 are ignored.
	   (Eg: Those pesky "From " lines should not show up anymore --
	    please do not confuse this with the regular "From:" lines;
	    note the colon vs the space).

	o  New resources:

		BOTLINKS	- May be used to completely customize
				  the links at the bottom of messages.
		IDXPGBEGIN	- Opening markup for main index page.
				  Allows one to redefine opening HTML
				  element, HEAD element, TITLE element,
				  opening BODY element, etc.
		IDXPGEND	- Closing markup for main index page.
		IDXSIZE		- Set the maximum number of messages
				  listed in index.  This is different
				  in MAXSIZE where MAXSIZE will remove
				  older messages when the MAXSIZE limit
				  is reached in the archive.
		MIMEARGS	- Define arguments to filters
		MSGPGBEGIN	- Opening markup for message pages.
				  Allows one to redefine opening HTML
				  element, HEAD element, TITLE element,
				  opening BODY element, etc.
		MSGPGEND	- Closing markup for message pages.
		NEXTBUTTON	- Defines the 'Next' button.
		NEXTBUTTONIA	- Defines the 'Next' button when it is
				  inactive.
		NEXTLINK	- Defines the 'Next' link.
		NEXTLINKIA	- Defines the 'Next' link when it is
				  inactive.
		NOTSUBSORT	- Do not sort threads by subject.
		OTHERINDEXES	- List other resource files defining
				  other indexes to create when creating,
				  or updating, an archive.
		PREVBUTTON	- Defines the 'Prev' button.
		PREVBUTTONIA	- Defines the 'Prev' button when it is
				  inactive.
		PREVLINK	- Defines the 'Prev' link.
		PREVLINKIA	- Defines the 'Prev' link when it is
				  inactive.
		TIDXPGBEGIN	- Opening markup for thread index page.
				  Allows one to redefine opening HTML
				  element, HEAD element, TITLE element,
				  opening BODY element, etc.
		TIDXPGEND	- Closing markup for thread index page.
		TOPLINKS	- May be used to completely customize
				  the buttons at the top of messages.
		TSUBSORT	- Sort threads listed by subject.

	o  Removed resources:

		INDEXBL, INDEXFL, MBOX, MH, NEXTBL, NEXTFL, PREVBL,
		PREVFL, TINDEXBL, TINDEXFL

	   Resource were removed because they were no longer applicable
	   and/or have been superceded by other resources.  MHonArc
	   will still honor old resource settings (where applicable) of
	   older archives and incorporate them into the new resource
	   settings.

	o  When specifying the resource file, mhonarc will now do
	   the following to determine its location:

		1.  If its an absolute pathname, mhonarc uses it.
		2.  If it is a relative pathname, mhonarc checks for
		    it relative to the current working directory.
		3.  Otherwise, mhonarc checks for it relative to
		    location of the archive as specified by outdir.

	   This resolution will allow you to place resource files with
	   the archive if desired (can be useful when using the
	   OTHERINDEXES resource element).

	o  Because of the new resources available, many <HR>'s are no
	   longer hard-coded and are controllable by resources.  <HR>'s
	   are still used in message pages to separate message data
	   from mhonarc data.

	o  Added resource variables:
	   (NOTE: Some variables are only valid in certain contexts)

		$DDMMYY$	- Date of message in dd/mm/yy format
		$IDXSIZE$	- Max size of index list
		$MMDDYY$	- Date of message in mm/dd/yy format
		$MSGID$		- Message id
		$NEXTBUTTON$	- Next button markup
		$NEXTFROM$	- From field of next listed message
		$NEXTFROMADDR$	- From e-mail address of next listed message
		$NEXTFROMNAME$	- From name of next listed message
		$NEXTLINK$	- Next link markup
		$NEXTMSGNUM$	- Number of next listed message
		$NEXTSUBJECT$	- Subject text of next listed message
		$NUMOFIDXMSG$	- Number of messages in index list
		$PREVBUTTON$	- Previous button markup
		$PREVFROM$	- From field of previous listed message
		$PREVFROMADDR$	- From e-mail address of prev listed message
		$PREVFROMNAME$	- From name of previous listed message
		$PREVLINK$	- Previous link markup
		$PREVMSGNUM$	- Number of previous message
		$PREVSUBJECT$	- Subject text of previous listed message
		$YYMMDD$	- Date of message in yy/mm/dd format

	o  Can specify a 'U' with variable length specifier to denote
	   replacement string is to be used in a URL.  Examples:

		$SUBJECTNA:40U$
		$MSGID:U$

	   The 'U' causes the replace text to have special characters
	   escaped as denoted by the URL spec.  NOTE: Specify ":U"
	   should NOT be used in the MAILTOURL resource; the variables
	   will automatically be expanded according to the URL spec.
	   Specifyind ":U" or a length specifier in the MAILTOURL
	   resource will prevent mhonarc from detecting the variable.

	o  New command-line options:

		-genidx		- Generate HTML index of archive contents
				  to stdout.
		-idxsize	- Maximum number of messages shown in indexes
		-notsubsort	- Do not sort threads listed by subject.
		-savemem	- Write message data while processing
		-tsubsort	- Sort threads listed by subject.

	o  The library mhtxt2022.pl has been added that provides
	   a filter to process ISO-2022 (Japanese) encoded mail messages.
	   See mhtxt2022.pl on how to hook it in.

	o  The mhexternal.pl filter by default ignores any filename
	   specification in the message for creating derived files.
	   This avoids name conflicts and security problems.
	   The "usename" filter option may be used to override this.

	o  Mime filters are now called with two additional arguments:

		$converted_data = &function(
			$header, *parsed_header_assoc_array,
			*message_data, $decoded_flag,
			$optional_filter_arguments);

	   The $decoded_flag is set to 1 if the *message_data has been
	   decoded.  $optional_filter_arguments contains an optional
	   argument string as determined by the filter.

	o  Mime filters can now be registered for multipart types
	   and message types.  This allows one to override mhonarc's
	   conversion of these types, and completely replace mhonarc's
	   message->HTML conversion process.

	o  Mime filters should now use $'FieldSep instead of $'X for
	   accessing parsed message headers.

	o  Mime filters can be registered for a base type.  Ie.
	   It is no longer required to explicitly list each possible
	   subtype if a single filter is to be used for them all.
	   Example:

		<mimefilters>
		image/*:myfilter'imagefilter:myfilter.pl
		</mimefilters>

	   Registers "myfilter'filter" for all image data types,
	   regardless of subtype.  However, if an explicit entry
	   exists for a subtype, then that filter is called.
	   Example:

		<mimefilters>
		image/*:myfilter'imagefilter:myfilter.pl
		image/gif:myfilter'giffilter:myfilter.pl
		</mimefilters>

	   "myfilter'giffilter" is called for all image/gif data.
	   "myfilter'imagefilter" is called for all other image data.

	o  A new resource, MIMEARGS, may be used to pass optional arguments
	   to filters to control their behavior.  The format of the
	   argument string is controlled by the various filters.  The
	   arguments can be specified by a specific content-type, or
	   for the filter routine in general.  A content-type argument
	   will be used over any arguments specified for a filter.

	   Example usage:

		<mimeargs>
		image/gif:inline usename
		m2h_external'filter:usename
		</mimeargs>

	   See the documentation for possible arguments to filters.

	o  Installation program can now be invoked in batch mode.

	o  Thread index properly includes docurl as main index.
	   -nodocurl will prevent the inclusion as with the main index.

	o  Fixed bug in mhtxthtml.pl on properly propogating a base
	   URL to relative URLs starting with a "/".

	o  Fixed bug where single quotes, and backslashed in keys of
	   associative arrays in the database file were not getting
	   escaped.

	o  Fixed bug where spaces and special characters were not
	   properly escaped in URL strings: spaces were left as-is,
	   and special characters were deleted.

	o  Removed illegal invocation choices in the Synopsis of the
	   documentation.

=======================================================================
1995/04/24	(1.1.1)

	o  Fixed bug in -scan output where month in date was off by
	   one.

=======================================================================
1995/04/21	(1.1.0)

	o  Made modifications to make MHonArc suitable to run
	   under MS-DOS without modification.  MHonArc will
	   automatically detect if it is running under Unix or MS-DOS.

	o  Added support for a thread index.  MHonArc will create a
	   complimentary index to the main index showing message
	   threads.

	o  Archive messages can be deleted.

	o  A listing to stdout of an archives contents can be
	   generated.

	o  Maximum number of messages for an archive can be set.
	   Older messages (based on sort method) are removed
	   automatically during add operations.

	o  MHonArc will now recognize if you try to add in a message
	   that already exists in an archive.

	o  The -editdx option will now also cause a updating of all
	   mail messages.  Guarantees resource changes to affect all
	   messages.

	o  Added the following resource file elements:

		MSGFOOT		-- Footer text for converted messages
		MSGHEAD		-- Header text for converted messages
		NODOC		-- Do not put link to documentation
		NOTHREAD	-- Do not create thread index
		TFOOT		-- Text at bottom of thread index page
		THEAD		-- Text at top of thread index page
		THREAD		-- Create thread index
		TLEVELS		-- Depth of thread listing
		TLITXT		-- Template text for entry in thread
				   index
		TIDXFNAME	-- Thread index filename
		TINDEXBL	-- Top button label in messages to
				   thread index
		TINDEXFL	-- Verbose label in message to thread
				   index
		TTITLE		-- Title of thread index page

	o  Added the following command-line options:

		-maxsize	-- Maxinum # messages in an archive
		-nodoc		-- Do not put link to documentation
		-nothread	-- Do not create thread index
		-rmm		-- Remove messages from an archive
		-scan		-- Listing of archive to stdout
		-thread		-- Create thread index
		-tidxfname	-- Thread index filename
		-tlevels	-- Depth of thread listing
		-ttitle		-- Title of thread index page

	o  Added the following environment variables:

		M2H_MAXSIZE	-- Maxinum # messages in an archive
		M2H_THREAD	-- If non-zero, create thread index
		M2H_TIDXFNAME	-- Thread index filename
		M2H_TLEVELS	-- Depth of thread listing
		M2H_TTITLE	-- Title of thread index page

	o  Added the following variables for template resources
	   (applicability of variables vary depending on the resource):

		$DOCURL$	-- URL to documentation
		$IDXFNAME$	-- Main index page filename
		$IDXTITLE$	-- Main index page title
		$NEXTMSG$	-- Next message filename
		$PREVMSG$	-- Previous message filename
		$PROG$		-- Program name
		$TIDXFNAME$	-- Thread index page filename
		$TIDXTITLE$	-- Thread index page title
		$VERSION$	-- Version number of the program

	o  Added $FROM$, $MSGID$, and $SUBJECT$ variables to be used
	   in the MAILTOURL resource.

	o  The string `$$' in template resources will produce a `$' in
	   the output.

	o  Fixed problem with messages (with follow-ups) getting
	   unnecessarily updated when messages are added to an archive.

	o  Only a CR/LF, or LF, pair will terminate a message head.
	   Before, MHonArc was terminating message heads when
	   encountering an empty line or a line that only contained
	   whitespace (which was incorrect behavior).

	o  Fixed bug in mhexternal.pl dealing with the `name' parameter
	   in the content-type field.  Surrounding "s or 's were not
	   being deleted causing filenames with quotes to be written.

	o  mhexternal.pl: The head of a pathname in the `name'
	   parameter in the content-type field is stripped off before
	   writing the external file.  I.e. Only the base filename is
	   used.

	o  Only one <HR> after the H1 subject in messages will appear
	   if no message header fields are printed.

	o  Added recognition of the following content-types in
	   mhexternal.pl:

		application/mac-binhex40

	o  Added a extras/ directory containing useful programs for
	   MHonArc.  See README in the directory for information on
	   the programs contained in there.

	o  To support -rmm, MIME filters now return an array.  The
	   first array value is the HTML for the message, and any other
	   array values are filenames of files generated by the
	   filter.  This allows MHonArc to know of any extra files that
	   must be deleted when a message is removed.

	o  Some routines from the main mhonarc source file have been
	   moved into a separate librarys: readmail.pl, mhdb.pl,
	   mhutil.pl

	o  The default URL to the documentation is now,

		http://www.oac.uci.edu/indiv/ehood/mhonarc.html

	   The old URL,

		http://www.oac.uci.edu/indiv/ehood/mhonarc.doc.html

	   is still valid.

	o  There's probably other stuff, but I cannot remember.

=======================================================================
1994/10/01	(1.0.0)

	o  First release -- See RELNOTES about compatibility issues
	   with mail2html.

=======================================================================
Earl Hood, mhonarc@mhonarc.org
$Id: CHANGES,v 1.159 2012/01/29 19:45:55 ehood Exp $
