Changes from 2.4.0 to 2.4.1

    * SECURITY: Handle the special filing of control messages into per-type
      newsgroups more robust.  This closes a potentially exploitable buffer
      overflow.  Thanks to Dan Riley for his excellent bug report.

    * Fixed article handling in innd so that articles without a Path header
      (arising from peers sending malformatted articles or injecting
      malformatted articles through rnews) would not cause innd to crash. 
      (This was not exploitable.)

    * Fixed a serious bug in XPAT handling, thanks to Tommy van Leeuwen.

    * configure now looks for sendmail only in /usr/sbin and /usr/lib, not
      on the user's path.  This should reduce the need for --with-sendmail
      if your preferred sendmail is in a standard location.

    * The robustness of the tradindexed overview method has been further
      increased, handling more edge cases arising from corrupted databases
      and oddly-named newsgroups.

    * innd now never decreases the high water mark of a newsgroup when
      renumbering, which should help ameliorate overview and active file
      synchronization problems.

    * Do not close and reopen the history file on ctlinnd reload when the
      server is paused or throttled.  This was breaking ctlinnd reload all
      during a server pause.

    * Various minor portability and compilation issues fixed.  Substantial
      numbers of compiler warnings have been cleaned up, thanks largely to
      work by Ilya Kovalenko.

    * Multiple other more minor bugs have been fixed.

    * Documentation and man pages have been clarified and updated.

Upgrading from 2.3 to 2.4

    The inn.conf parser has changed between INN 2.3 and 2.4.  Due to that
    change, options in inn.conf that contain whitespace or a few other
    special characters must be quoted with double quotes, and empty
    parameters (parameters with no value) are not allowed.  INN 2.4 comes
    with a script, innupgrade, run automatically during "make update", that
    will attempt to fix any problems that it finds with your inn.conf file,
    saving the original as inn.conf.OLD.

    This change is the beginning of standardization of parsing and syntax
    across all of INN's configuration files.

    The history subsystem now has a standard API that allows other backends
    to be used.  Because of this, you now need to specify the history method
    in inn.conf.  Adding:

        hismethod: hisv6

    will tell INN to use the same history backend as was used in previous
    versions.  innupgrade should take care of this for you.

    ovdb is known to have some locking and timing issues related to how
    nnrpd shuts down (or fails to shut down) the overview databases.  If you
    have stability problems with ovdb, try setting readserver to true in
    ovdb.conf.  This will funnel all ovdb reads through a single process
    with a cleaner interface to the underlying BerkeleyDB database.

    If you use Perl authentication for nnrpd (if *nnrpdperlauth* in inn.conf
    is true), there have been major changes.  See "Changes to Perl
    Authentication Support for nnrpd" in doc/hook-perl for details.

    Similarly, if you use Python authentication for nnrpd (if
    *nnrpdpythonauth* in inn.conf is true), there have been major changes. 
    See "Changes to Python Authentication and Access Control Support for
    nnrpd" in doc/hook-python for details.

    If you use send-uucp, it has been completely rewritten and now takes a
    configuration file to specify its behavior.  See its man page for more
    information.  If you use sendbatch, it is no longer included in INN
    since the new send-uucp can handle all of the same functionality.

    The wildmat API has been renamed (to uwildmat and friends; see
    uwildmat(3) for the interfaces) to distinguish it from Rich $alz's
    original version, since it now supports UTF-8.  This may require changes
    in other software packages that link against INN's libraries.

    If you are upgrading from a version prior to INN 2.3, see "Upgrading
    from 2.2 to 2.3".

Changes from 2.3 to 2.4

    * IPv6 support has been added, disabled by default.  If you have IPv6
      connectivity, build with --enable-ipv6 to try it.  There are no known
      bugs, but please report any problems you find (or even successes, if
      you use an unusual platform).  There are a few changes of interest;
      further information is available in doc/IPv6-info.

    * The tradindexed overview method has been completely rewritten and
      should be considerably more robust in the face of system crashes.  A
      new utility, tdx-util, is provided to examine the contents of the
      overview database, repair inconsistencies, and rebuild the overview
      for particular groups from a tradspool news spool.  See tdx-util(8)
      for more details.

    * The Perl and Python authentication hooks for readers have been
      extensively overhauled and integrated better with readers.conf.  See
      the Changes sections in doc/hook-perl and doc/hook-python for more
      details.

    * nnrpd now optionally supports article injection via IHAVE, see
      readers.conf(5).  Any articles injected this way must have Date, From,
      Message-ID, Newsgroups, Path, and Subject headers.  X-Trace and
      X-Complaints-To headers will be added if the appropriate options are
      set in readers.conf, but other headers will not be modified/inserted
      (e.g.  NNTP-Posting-Host, NNTP-Posting-Date, Organization, Lines, Cc,
      Bcc, and To headers).

    * nnrpd now handles arbitrarily long lines in POST and IHAVE;
      administrators who want to limit the length of lines in locally posted
      articles will need to add this to their local filters instead.

    * nnrpd no longer handles the poorly-specified RFC 977 optional fourth
      argument to the NEWGROUPS command specifying the "distributions" that
      the command was supposed to apply to.

      Clients that use that argument will break.  There are not believed to
      be any such clients, and it's easy enough to just filter the returned
      list of newsgroups (which is generally fairly short) to achieve the
      same results.

    * nnrpd no longer accepts UTC as a synonym for GMT for NEWGROUPS or
      NEWNEWS.  This usage was never portable, and was rejected by the NNTP
      working group.  It is being removed now in the hope that it will be
      caught before anyone starts to rely on it.

    * innfeed supports a new peer parameter, *backlog-feed-first*, that if
      set to true feeds any backlog to a peer before new articles, see
      innfeed.conf(5).  When used in combination with *max-connections: 1*,
      this can be used to enforce in-order delivery of messages to a peer
      that is doing Xref slaving, avoiding cases where a higher-numbered
      message is received before a lower-numbered message in the same group.

    * Several other, more minor protocol issues have been fixed: 
      connections rejected due to the connection rate limiting in innd
      receive 400 replies instead of 504 or 505, and ARTICLE without an
      argument will always either retrieve the current article or return a
      423 error, never advance the current article number to the next valid
      article.

      See doc/compliance-nntp for all of the known issues with INN's
      compliance with the current NNTP draft.

    * All accesses to the history file for all parts of INN now go through a
      generic API like the storage and overview subsystems do.  This will
      eventually allow new history implementations to be dropped in without
      affecting the rest of INN, and will significantly improve the
      encapsulation of the history subsystem.  See the libinnhist(3) man
      page for the details of the interface.

    * INN now uses a new parser for the inn.conf file.  This means that
      parameters containing whitespace or other special characters must now
      be quoted; see inn.conf(5).  It fixes the long-standing bug that
      certain values must be included in inn.conf even if using the defaults
      for the use of shell or Perl scripts, and it will serve as the basis
      for standardizing and cleaning up the configuration file parsing in
      other parts of INN.  innupgrade is run during make update and should
      convert an existing inn.conf file for you.

    * send-uucp has been replaced by a completely rewritten version from
      Marco d'Itri, Edvard Tuinder, and Miquel van Smoorenburg, which uses a
      configuration file that specifies batch sizes, compression methods,
      and hours during which batches should be generated.  The old sendbatch
      script has been retired, since send-uucp can now handle everything
      that it did.

    * Two configure options have changed names:  --with-tmp-path is now
      --with-tmp-dir, and --with-largefiles is now --enable-largefiles, to
      improve consistency and better match the autoconf option guidelines.

    * Variables can now be used in the newsfeeds file to make it easier to
      specify many similar feeds or feed patterns.  See the newsfeeds(5) man
      page for details.

    * Local connections to INN support a new special mode, MODE CANCEL, that
      allows efficient batch cancellation of messages.  This is intended to
      be the preferred interface for external spam and abuse filters like
      NoCeM.  See "CANCEL FEEDS" in innd(8) for details.

    * Two new options, *nfsreader* and *nfswriter*, have been added to
      inn.conf to aid in building NFS based shared reader/writer platforms. 
      On the writer server configure nfswriter to true and on all of the
      readers configure nfsreader to true; these options add calls to force
      data out to the NFS server and force it to be read directly from the
      NFS server at the appropriate moments.  Note that it has only been
      tested on Solaris 8, using CNFS as the storage mechanism and
      tradindexed as the overview method.

    * A new option, *tradindexedmmap*, has been added to inn.conf.  If set
      to true (the default), then the tradindexed overview method will use
      mmap() to access its overview data (in 2.3 you couldn't control this;
      it always used mmap).

    * Thanks to code contributed by CMU, innfeed can now feed an IMAP server
      as well as other NNTP servers.  See the man page for innfeed(8) for
      more information.

    * An authenticator, auth_smb, that checks a username and password
      against a remote Samba server is now included.  See auth_smb(8) for
      details.

    * The wildmat functions in INN now support UTF-8, in a way that should
      allow them to still work with most simple 8-bit character sets in
      widespread use.  As part of this change, some additional wildmat
      interfaces are now available and the names have changed (to uwildmat,
      where u is for Unicode).  See uwildmat(3) for the details.

    * The interface between external authenticators and nnrpd is now
      properly documented, in doc/external-auth.  A library implementing
      this interface in C is provided, which should make it easier to write
      additional authenticators resolvers.  See libauth(3) for details, and
      any of the existing programs in authprogs/ for examples.

    * INN now checks to ensure that the configured temporary directory is
      not world-writeable.  Additionally, most (if not all) of the temporary
      file creation in INN now uses functions that create temporary files
      properly and safely.

    * All of the applicable bug fixes from the INN 2.3 STABLE series are
      also included in INN 2.4.

Upgrading from 2.2 to 2.3

    There may be additional things to watch out for not listed here; if you
    run across any, please let inn-bugs@isc.org know about them.

    Simply doing a make update is not sufficient to upgrade; the history and
    overview information will also have to be regenerated, since the formats
    of both files have changed between 2.2 and 2.3.  Regardless of whether
    you were using the storage API or traditional spool under 2.2, you'll
    need to rebuild your overview and history files.  You will also need to
    add a storage.conf file, if you weren't using the storage API under INN
    2.2.  A good default storage.conf file for 2.2 users would be:

        method tradspool {
            newsgroups: *
            class: 0
        }

    Create this storage.conf file before rebuilding history or overview.

    If you want to allow readers, or if you want to expire based on
    newsgroup name, you need to tell INN to generate overview data and pick
    an overview method by setting *ovmethod* in inn.conf.  See INSTALL and
    inn.conf(5) for more details.

    The code that generates the dbz index files has been split into a
    seperate program, makedbz.  makehistory still generates the base history
    file and the overview information, but some of its options have been
    changed.  To rebuild the history and overview files, use something like:

        makehistory -b -f history.n -O -T/usr/local/news/tmp -l 600000

    (change the /usr/local/news/tmp path to some directory that has plenty
    of temporary space, and leave off -O if you're running a transit-only
    server and don't intend to expire based on group name, and therefore
    don't need overview.)  Or if your overview is buffindexed, use:

        makehistory -b -f history.n -O -F

    Both will generate a new history file as history.n and rebuild overview
    at the same time.  If you want to preseve a record of expired message
    IDs in the history file, run:

        awk 'NF==2 { print; }' < history >> history.n

    to append them to the new history file you created above.  Look over the
    new history file and make sure it looks right, then generate the new
    index files and move them into place:

        makedbz -s `wc -l <history.n` -f history.n
        mv history.n history
        mv history.n.dir history.dir
        mv history.n.hash history.hash
        mv history.n.index history.index

    (Rather than .hash and .index files, you may have a .pag file if you're
    using tagged hash.)

    For reader machines, nnrp.access has been replaced by readers.conf. 
    There currently isn't a program to convert between the old format and
    the new format (if you'd like to contribute one, it would be welcomed
    gratefully).  The new file is unfortunately considerably more complex as
    a result of its new capabilities; please carefully read the example
    readers.conf provided and the man page when setting up your initial
    configuration.  The provided commented-out examples cover the most
    common installation (IP-based authentication for all machines on the
    local network).

    INN makes extensive use of mmap(2) for the new overview mechanisms, so
    at the present time NFS-mounting the spool and overview on multiple
    reader machines from one central server probably isn't feasible in this
    version.  mmap tends to interact poorly with NFS (at the least, NFS
    clients won't see updates to the mapped files in situations where they
    should).  (The preferred way to fix this would, rather than backing out
    the use of mmap or making it optional, to add support for Diablo-style
    header feeds and pull-on-demand of articles from a master server.)

    The flags for overchan have changed, plus you probably don't want to run
    overchan at all any more.  Letting innd write overview data itself
    results in somewhat slower performance, but is more reliable and has a
    better failure mode under high loads.  Writing overview data directly is
    the default, so in a normal upgrade from 2.2 to 2.3 you'll want to
    comment out or remove your overchan entry in newsfeeds and set
    useoverchan to false in inn.conf.

    crosspost is no longer installed, and no longer works (even with
    traditional spool).  If you have an entry for crosspost in newsfeeds,
    remove it.

    If you're importing a traditional spool from a pre-storage API INN
    server, it's strongly recommended that you use NNTP to feed the articles
    to your new server rather than trying to build overview and history
    directly from the old spool.  It's more reliable and ensures that
    everything gets put into the right place.  The easiest way to do this is
    to generate, on your old server, a list of all of your existing article
    files and then feed that list to innxmit.  Further details can be found
    in the FAQ at *http://www.eyrie.org/~eagle/faqs/inn.html*.

    If you are using a version of Cleanfeed that still has a line in it
    like:

        $lines = $hdr{'__BODY__'} =~ tr/\n/\n/;

    you will need to change this line to:

        $lines = $hdr{'__LINES__'};

    to work with INN 2.3 or later.  This is due to an internal optimization
    of the interface to embedded filters that's new in INN 2.3.

Changes from 2.2 to 2.3

    * New readers.conf file (replaces nnrp.access) which allows more
      flexible specification of access restrictions.  Included in the sample
      implementations is a RADIUS-based authenticator.

    * Unified overview has been replaced with an overview API, and there are
      now three separate overview implementations to choose from.  One
      (tradindexed) is very like traditional overview but uses an additional
      index file.  The second (buffindexed) uses large buffers rather than
      separate files for each group and can handle a higher incoming article
      rate while still being fast for readers.  The third (ovdb) uses
      Berkeley DB to store overview information (so you need to have
      Berkeley DB installed to use it).  The *ovmethod* key in inn.conf
      chooses the overview method to use.

      Note that ovdb has not been as widely tested as the other overview
      mechanisms and should be considered experimental.

    * All article storage and retrieval is now done via the storage API. 
      Traditional spool is now available as a storage type under the storage
      API.  (Note that the current traditional spool implementation causes
      nightly expire to be extremely slow for a large number of articles, so
      it's not recommended that you use the tradspool storage method for the
      majority of a large spool.)

    * The timecaf storage method has been added, similar to timehash but
      storing multiple articles in a single file.  See INSTALL for details
      on it.

    * INN now supports embedded Python filters as well as Perl and TCL
      filters, and supports Python authentication hooks.

    * There is preliminary support for news reading over SSL, using OpenSSL.

    * Users can no longer post articles containing Approved: headers to
      moderated groups by default; they must be specifically given that
      permission with the access: parameter in readers.conf.  See the man
      page for more details.

    * To simplify anti-abuse filtering, and to be more compliant with news
      standards and proposed standards, INN now treats as control messages
      only articles containing a Control header.  A Subject line beginning
      with "cmsg " is no longer sufficient for a message to be considered a
      control message, and the Also-Control header is no longer supported.

    * inews is not installed setgid news and rnews is not installed setuid
      root by default any more.  If you need the old permissions, you have
      to give a flag to configure.  See INSTALL for more details.

    * The INN build system no longer uses subst.  (This will be transparent
      to most users; it's an improvement and modernization of how INN is
      configured.)

    * The build and installation system has been substantially overhauled. 
      "make update" now updates scripts as well as binaries and
      documentation, there is better support for parallel builds ("make
      -j"), there is less make recursion, and far more of the
      system-dependent configuration is handled directly by autoconf. 
      libtool build support (including shared library support) should be
      better than previous releases.

    * All of the applicable bug fixes from the INN 2.2 STABLE series are
      also included in INN 2.3.

Changes from 2.1 to 2.2

    * New storage.conf file (replaces storage.ctl).

    * New (optional) way of handling non-cancel control messages
      (controlchan) that serializes them and prevents server overload from
      control message storms.

    * Support for actsyncd to fetch active file with ftp; configured by
      default to use <ftp://ftp.isc.org/pub/usenet/CONFIG/active.Z> if you
      run actsyncd.  Be sure to read the manual page for actsync to
      configure an actsync.ign file for your site, and test simpleftp if you
      do not configure with wget or ncftp.  Also see
      <ftp://ftp.isc.org/pub/usenet/CONFIG/README>.

    * Some options to configure are now moved to inn.conf (merge-to-groups
      and pgp-verify).

    * inndf, a portable version of df(1), is supplied.

    * New cnfsstat program to show stats of cnfs buffers.

    * news2mail and mailpost programs for gatewaying news to mail and mail
      to news are supplied.

    * pullnews program for doing a sucking feed is provided (not meant for
      large feeds).

    * The innshellvars.csh.in script is obsolete (and lives in the obsolete
      directory, for now).

