Version 4.68
------------

 1. The body_linecount and body_zerocount C variables are now exported in the
    local_scan API.

 2. When a dnslists lookup succeeds, the key that was looked up is now placed
    in $dnslist_matched. When the key is an IP address, it is not reversed in
    this variable (though it is, of course, in the actual lookup). In simple
    cases, for example:

      deny dnslists = spamhaus.example

    the key is also available in another variable (in this case,
    $sender_host_address). In more complicated cases, however, this is not
    true. For example, using a data lookup might generate a dnslists lookup
    like this:

      deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...

    If this condition succeeds, the value in $dnslist_matched might be
    192.168.6.7 (for example).

 3. Authenticators now have a client_condition option. When Exim is running as
    a client, it skips an authenticator whose client_condition expansion yields
    "0", "no", or "false". This can be used, for example, to skip plain text
    authenticators when the connection is not encrypted by a setting such as:

      client_condition = ${if !eq{$tls_cipher}{}}

    Note that the 4.67 documentation states that $tls_cipher contains the
    cipher used for incoming messages. In fact, during SMTP delivery, it
    contains the cipher used for the delivery. The same is true for
    $tls_peerdn.

 4. There is now a -Mvc <message-id> option, which outputs a copy of the
    message to the standard output, in RFC 2822 format. The option can be used
    only by an admin user.

 5. There is now a /noupdate option for the ratelimit ACL condition. It
    computes the rate and checks the limit as normal, but it does not update
    the saved data. This means that, in relevant ACLs, it is possible to lookup
    the existence of a specified (or auto-generated) ratelimit key without
    incrementing the ratelimit counter for that key.

    In order for this to be useful, another ACL entry must set the rate
    for the same key somewhere (otherwise it will always be zero).

    Example:

    acl_check_connect:
      # Read the rate; if it doesn't exist or is below the maximum
      # we update it below
      deny ratelimit = 100 / 5m / strict / noupdate
           log_message = RATE: $sender_rate / $sender_rate_period \
                         (max $sender_rate_limit)

      [... some other logic and tests...]

      warn ratelimit = 100 / 5m / strict / per_cmd
           log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
                         (max $sender_rate_limit)
           condition = ${if le{$sender_rate}{$sender_rate_limit}}

      accept

 6. The variable $max_received_linelength contains the number of bytes in the
    longest line that was received as part of the message, not counting the
    line termination character(s).

 7. Host lists can now include +ignore_defer and +include_defer, analagous to
    +ignore_unknown and +include_unknown. These options should be used with
    care, probably only in non-critical host lists such as whitelists.

 8. There's a new option called queue_only_load_latch, which defaults true.
    If set false when queue_only_load is greater than zero, Exim re-evaluates
    the load for each incoming message in an SMTP session. Otherwise, once one
    message is queued, the remainder are also.

 9. There is a new ACL, specified by smtp_notquit_acl, which is run in most
    cases when an SMTP session ends without sending QUIT. However, when Exim
    itself is is bad trouble, such as being unable to write to its log files,
    this ACL is not run, because it might try to do things (such as write to
    log files) that make the situation even worse.

    Like the QUIT ACL, this new ACL is provided to make it possible to gather
    statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
    modifier is forbidden in this ACL.

    When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
    to a string that indicates the reason for the termination of the SMTP
    connection. The possible values are:

      acl-drop                 Another ACL issued a "drop" command
      bad-commands             Too many unknown or non-mail commands
      command-timeout          Timeout while reading SMTP commands
      connection-lost          The SMTP connection has been lost
      data-timeout             Timeout while reading message data
      local-scan-error         The local_scan() function crashed
      local-scan-timeout       The local_scan() function timed out
      signal-exit              SIGTERM or SIGINT
      synchronization-error    SMTP synchronization error
      tls-failed               TLS failed to start

    In most cases when an SMTP connection is closed without having received
    QUIT, Exim sends an SMTP response message before actually closing the
    connection. With the exception of acl-drop, the default message can be
    overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
    "drop" verb in another ACL, it is the message from the other ACL that is
    used.

10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
    servers with individual queries. This is done by starting the query with
    "servers=x:y:z;", where each item in the list may take one of two forms:

    (1) If it is just a host name, the appropriate global option (mysql_servers
        or pgsql_servers) is searched for a host of the same name, and the
        remaining parameters (database, user, password) are taken from there.

    (2) If it contains any slashes, it is taken as a complete parameter set.

    The list of servers is used in exactly the same was as the global list.
    Once a connection to a server has happened and a query has been
    successfully executed, processing of the lookup ceases.

    This feature is intended for use in master/slave situations where updates
    are occurring, and one wants to update a master rather than a slave. If the
    masters are in the list for reading, you might have:

      mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw

    In an updating lookup, you could then write

      ${lookup mysql{servers=master; UPDATE ...}

    If, on the other hand, the master is not to be used for reading lookups:

      pgsql_servers = slave1/db/name/pw:slave2/db/name/pw

    you can still update the master by

      ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}

11. The message_body_newlines option (default FALSE, for backwards
    compatibility) can be used to control whether newlines are present in
    $message_body and $message_body_end. If it is FALSE, they are replaced by
    spaces.

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