X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/4730f9424e0addeb902cc842508eea3f47a131ca..fa1fce6bfaeba9f94c90d279bb8f66f5b38db349:/doc/doc-txt/NewStuff diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index c807d931b..3a3ad5de5 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,91 +1,580 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.90 2006/02/23 12:41:22 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.176 2010/06/14 18:51:10 pdp Exp $ New Features in Exim -------------------- -This file contains descriptions of new features that have been added to Exim, -but have not yet made it into the main manual (which is most conveniently -updated when there is a relatively large batch of changes). The doc/ChangeLog -file contains a listing of all changes, including bug fixes. +This file contains descriptions of new features that have been added to Exim. +Before a formal release, there may be quite a lot of detail so that people can +test from the snapshots or the CVS before the documentation is updated. Once +the documentation is updated, this file is reduced to a short list. + + +Version 4.74 +------------ + + 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux) + the flaw permitted the Exim run-time user to cause root to append to + arbitrary files of the attacker's choosing, with the content based + on content supplied by the attacker. + + 2. Exim now supports loading some lookup types at run-time, using your + platform's dlopen() functionality. This has limited platform support + and the intention is not to support every variant, it's limited to + dlopen(). This permits the main Exim binary to not be linked against + all the libraries needed for all the lookup types. + + +Version 4.73 +------------ + + NOTE: this version is not guaranteed backwards-compatible, please read the + items below carefully + + 1. A new main configuration option, "openssl_options", is available if Exim + is built with SSL support provided by OpenSSL. The option allows + administrators to specify OpenSSL options to be used on connections; + typically this is to set bug compatibility features which the OpenSSL + developers have not enabled by default. There may be security + consequences for certain options, so these should not be changed + frivolously. + + 2. A new pipe transport option, "permit_coredumps", may help with problem + diagnosis in some scenarios. Note that Exim is typically installed as + a setuid binary, which on most OSes will inhibit coredumps by default, + so that safety mechanism would have to be overriden for this option to + be able to take effect. + + 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless + Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes + Note that this switches Exim to use a new API ("INSTREAM") and a future + release of ClamAV will remove support for the old API ("STREAM"). + + The av_scanner option, when set to "clamd", now takes an optional third + part, "local", which causes Exim to pass a filename to ClamAV instead of + the file content. This is the same behaviour as when clamd is pointed at + a Unix-domain socket. For example: + + av_scanner = clamd:192.0.2.3 1234:local + + ClamAV's ExtendedDetectionInfo response format is now handled. + + 4. There is now a -bmalware option, restricted to admin users. This option + takes one parameter, a filename, and scans that file with Exim's + malware-scanning framework. This is intended purely as a debugging aid + to ensure that Exim's scanning is working, not to replace other tools. + Note that the ACL framework is not invoked, so if av_scanner references + ACL variables without a fallback then this will fail. + + 5. There is a new expansion operator, "reverse_ip", which will reverse IP + addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples: + + ${reverse_ip:192.0.2.4} + -> 4.2.0.192 + ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3} + -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 + + 6. There is a new ACL control called "debug", to enable debug logging. + This allows selective logging of certain incoming transactions within + production environments, with some care. It takes two options, "tag" + and "opts"; "tag" is included in the filename of the log and "opts" + is used as per the -d command-line option. Examples, which + don't all make sense in all contexts: + + control = debug + control = debug/tag=.$sender_host_address + control = debug/opts=+expand+acl + control = debug/tag=.$message_exim_id/opts=+expand + + 7. It has always been implicit in the design and the documentation that + "the Exim user" is not root. src/EDITME said that using root was + "very strongly discouraged". This is not enough to keep people from + shooting themselves in the foot in days when many don't configure Exim + themselves but via package build managers. The security consequences of + running various bits of network code are severe if there should be bugs in + them. As such, the Exim user may no longer be root. If configured + statically, Exim will refuse to build. If configured as ref:user then Exim + will exit shortly after start-up. If you must shoot yourself in the foot, + then henceforth you will have to maintain your own local patches to strip + the safeties off. + + 8. There is a new expansion operator, bool_lax{}. Where bool{} uses the ACL + condition logic to determine truth/failure and will fail to expand many + strings, bool_lax{} uses the router condition logic, where most strings + do evaluate true. + Note: bool{00} is false, bool_lax{00} is true. + + 9. Routers now support multiple "condition" tests, + +10. There is now a runtime configuration option "tcp_wrappers_daemon_name". + Setting this allows an admin to define which entry in the tcpwrappers + config file will be used to control access to the daemon. This option + is only available when Exim is built with USE_TCP_WRAPPERS. The + default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME + build option. + +11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now + the Exim run-time user, instead of root. + +12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and + is forced on. This is mitigated by the new build option + TRUSTED_CONFIG_LIST which defines a list of configuration files which + are trusted; one per line. If a config file is owned by root and matches + a pathname in the list, then it may be invoked by the Exim build-time + user without Exim relinquishing root privileges. + +13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically + trusted to supply -D overrides on the command-line. Going + forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that + include the main config. As a transition mechanism, we are temporarily + providing a work-around: the new build option WHITELIST_D_MACROS provides + a colon-separated list of macro names which may be overriden by the Exim + run-time user. The values of these macros are constrained to the regex + ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values). + + +Version 4.72 +------------ + + 1. TWO SECURITY FIXES: one relating to mail-spools which are globally + writable, the other to locking of MBX folders (not mbox). + + 2. MySQL stored procedures are now supported. + + 3. The dkim_domain transport option is now a list, not a single string, and + messages will be signed for each element in the list (discarding + duplicates). + + 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups + in the presence of multiple character strings within the RR. Prior to 4.70, + only the first string would be returned. The dnsdb lookup now, by default, + preserves the pre-4.70 semantics, but also now takes an extended output + separator specification. The separator can be followed by a semicolon, to + concatenate the individual text strings together with no join character, + or by a comma and a second separator character, in which case the text + strings within a TXT record are joined on that second character. + Administrators are reminded that DNS provides no ordering guarantees + between multiple records in an RRset. For example: + + foo.example. IN TXT "a" "b" "c" + foo.example. IN TXT "d" "e" "f" + + ${lookup dnsdb{>/ txt=foo.example}} -> "a/d" + ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc" + ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f" + + +Version 4.70 / 4.71 +------------------- + + 1. Native DKIM support without an external library. + (Note that if no action to prevent it is taken, a straight upgrade will + result in DKIM verification of all signed incoming emails. See spec + for details on conditionally disabling) + + 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha). + + 3. There is now a bool{} expansion condition which maps certain strings to + true/false condition values (most likely of use in conjunction with the + and{} expansion operator). + + 4. The $spam_score, $spam_bar and $spam_report variables are now available + at delivery time. + + 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as + options, provided that Exim is invoked by an admin_user. + + 6. There is a new option gnutls_compat_mode, when linked against GnuTLS, + which increases compatibility with older clients at the cost of decreased + security. Don't set this unless you need to support such clients. + + 7. There is a new expansion operator, ${randint:...} which will produce a + "random" number less than the supplied integer. This randomness is + not guaranteed to be cryptographically strong, but depending upon how + Exim was built may be better than the most naive schemes. + + 8. Exim now explicitly ensures that SHA256 is available when linked against + OpenSSL. + + 9. The transport_filter_timeout option now applies to SMTP transports too. + + +Version 4.69 +------------ + + 1. Preliminary DKIM support in Experimental. + + +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 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 acl_smtp_notquit, 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. + + +Version 4.67 +------------ + + 1. There is a new log selector called smtp_no_mail, which is not included in + the default setting. When it is set, a line is written to the main log + whenever an accepted SMTP connection terminates without having issued a + MAIL command. + + 2. When an item in a dnslists list is followed by = and & and a list of IP + addresses, the behaviour was not clear when the lookup returned more than + one IP address. This has been solved by the addition of == and =& for "all" + rather than the default "any" matching. + + 3. Up till now, the only control over which cipher suites GnuTLS uses has been + for the cipher algorithms. New options have been added to allow some of the + other parameters to be varied. + + 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is + set, Exim compiles a runtime option called disable_fsync. + + 5. There is a new variable called $smtp_count_at_connection_start. + + 6. There's a new control called no_pipelining. + + 7. There are two new variables called $sending_ip_address and $sending_port. + These are set whenever an SMTP connection to another host has been set up. + + 8. The expansion of the helo_data option in the smtp transport now happens + after the connection to the server has been made. + + 9. There is a new expansion operator ${rfc2047d: that decodes strings that + are encoded as per RFC 2047. + +10. There is a new log selector called "pid", which causes the current process + id to be added to every log line, in square brackets, immediately after the + time and date. + +11. Exim has been modified so that it flushes SMTP output before implementing + a delay in an ACL. It also flushes the output before performing a callout, + as this can take a substantial time. These behaviours can be disabled by + obeying control = no_delay_flush or control = no_callout_flush, + respectively, at some earlier stage of the connection. + +12. There are two new expansion conditions that iterate over a list. They are + called forany and forall. + +13. There's a new global option called dsn_from that can be used to vary the + contents of From: lines in bounces and other automatically generated + messages ("delivery status notifications" - hence the name of the option). + +14. The smtp transport has a new option called hosts_avoid_pipelining. + +15. By default, exigrep does case-insensitive matches. There is now a -I option + that makes it case-sensitive. + +16. A number of new features ("addresses", "map", "filter", and "reduce") have + been added to string expansions to make it easier to process lists of + items, typically addresses. + +17. There's a new ACL modifier called "continue". It does nothing of itself, + and processing of the ACL always continues with the next condition or + modifier. It is provided so that the side effects of expanding its argument + can be used. + +18. It is now possible to use newline and other control characters (those with + values less than 32, plus DEL) as separators in lists. + +19. The exigrep utility now has a -v option, which inverts the matching + condition. + +20. The host_find_failed option in the manualroute router can now be set to + "ignore". + + +Version 4.66 +------------ + +No new features were added to 4.66. + + +Version 4.65 +------------ + +No new features were added to 4.65. + + +Version 4.64 +------------ + + 1. ACL variables can now be given arbitrary names, as long as they start with + "acl_c" or "acl_m" (for connection variables and message variables), are at + least six characters long, with the sixth character being either a digit or + an underscore. + + 2. There is a new ACL modifier called log_reject_target. It makes it possible + to specify which logs are used for messages about ACL rejections. + + 3. There is a new authenticator called "dovecot". This is an interface to the + authentication facility of the Dovecot POP/IMAP server, which can support a + number of authentication methods. + + 4. The variable $message_headers_raw provides a concatenation of all the + messages's headers without any decoding. This is in contrast to + $message_headers, which does RFC2047 decoding on the header contents. + + 5. In a DNS black list, if two domain names, comma-separated, are given, the + second is used first to do an initial check, making use of any IP value + restrictions that are set. If there is a match, the first domain is used, + without any IP value restrictions, to get the TXT record. + + 6. All authenticators now have a server_condition option. + + 7. There is a new command-line option called -Mset. It is useful only in + conjunction with -be (that is, when testing string expansions). It must be + followed by a message id; Exim loads the given message from its spool + before doing the expansions. + + 8. Another similar new command-line option is called -bem. It operates like + -be except that it must be followed by the name of a file that contains a + message. + + 9. When an address is delayed because of a 4xx response to a RCPT command, it + is now the combination of sender and recipient that is delayed in + subsequent queue runs until its retry time is reached. + +10. Unary negation and the bitwise logical operators and, or, xor, not, and + shift, have been added to the eval: and eval10: expansion items. + +11. The variables $interface_address and $interface_port have been renamed + as $received_ip_address and $received_port, to make it clear that they + relate to message reception rather than delivery. (The old names remain + available for compatibility.) + +12. The "message" modifier can now be used on "accept" and "discard" acl verbs + to vary the message that is sent when an SMTP command is accepted. + + +Version 4.63 +------------ + +1. There is a new Boolean option called filter_prepend_home for the redirect + router. + +2. There is a new acl, set by acl_not_smtp_start, which is run right at the + start of receiving a non-SMTP message, before any of the message has been + read. + +3. When an SMTP error message is specified in a "message" modifier in an ACL, + or in a :fail: or :defer: message in a redirect router, Exim now checks the + start of the message for an SMTP error code. + +4. There is a new parameter for LDAP lookups called "referrals", which takes + one of the settings "follow" (the default) or "nofollow". + +5. Version 20070721.2 of exipick now included, offering these new options: + --reverse + After all other sorting options have bee processed, reverse order + before displaying messages (-R is synonym). + --random + Randomize order of matching messages before displaying. + --size + Instead of displaying the matching messages, display the sum + of their sizes. + --sort [,...] + Before displaying matching messages, sort the messages according to + each messages value for each variable. + --not + Negate the value for every test (returns inverse output from the + same criteria without --not). + + +Version 4.62 +------------ + +1. The ${readsocket expansion item now supports Internet domain sockets as well + as Unix domain sockets. If the first argument begins "inet:", it must be of + the form "inet:host:port". The port is mandatory; it may be a number or the + name of a TCP port in /etc/services. The host may be a name, or it may be an + IP address. An ip address may optionally be enclosed in square brackets. + This is best for IPv6 addresses. For example: + + ${readsocket{inet:[::1]:1234}{}... + + Only a single host name may be given, but if looking it up yield more than + one IP address, they are each tried in turn until a connection is made. Once + a connection has been made, the behaviour is as for ${readsocket with a Unix + domain socket. + +2. If a redirect router sets up file or pipe deliveries for more than one + incoming address, and the relevant transport has batch_max set greater than + one, a batch delivery now occurs. + +3. The appendfile transport has a new option called maildirfolder_create_regex. + Its value is a regular expression. For a maildir delivery, this is matched + against the maildir directory; if it matches, Exim ensures that a + maildirfolder file is created alongside the new, cur, and tmp directories. + Version 4.61 ------------ -PH/01 There is a new global option called disable_ipv6, which does exactly what - its name implies. If set true, even if the Exim binary has IPv6 support, - no IPv6 activities take place. AAAA records are never looked up for host - names given in manual routing data or elsewhere. AAAA records that are - received from the DNS as additional data for MX records are ignored. Any - IPv6 addresses that are listed in local_interfaces, manualroute route - data, etc. are also ignored. If IP literals are enabled, the ipliteral - router declines to handle IPv6 literal addresses. - -PH/02 There are now 20 of each type of ACL variable by default (instead of 10). - It is also possible to change the numbers by setting ACL_CVARS and/or - ACL_MVARS in Local/Makefile. Backward compatibility is maintained if you - upgrade to this release with existing messages containing ACL variable - settings on the queue. However, going in the other direction - (downgrading) will not be compatible; the values of ACL variables will be - lost. - -PH/03 If quota_warn_message contains a From: header, Exim now refrains from - adding the default one. Similarly, if it contains a Reply-To: header, the - errors_reply_to option, if set, is not used. - -PH/04 The variables $auth1, $auth2, $auth3 are now available in authenticators, - containing the same values as $1, $2, $3. The new variables are provided - because the numerical variables can be reset during string expansions - (for example, during a "match" operation) and so may lose the - authentication data. The preferred variables are now the new ones, with - the use of the numerical ones being deprecated, though the support will - not be removed, at least, not for a long time. - -PH/05 The "control=freeze" ACL modifier can now be followed by /no_tell. If - the global option freeze_tell is set, it is ignored for the current - message (that is, nobody is told about the freezing), provided all the - "control=freeze" modifiers that are obeyed in the current message have - the /no_tell option. - -PH/06 In both GnuTLS and OpenSSL, an expansion of tls_privatekey that results - in an empty string is now treated as unset. - -PH/07 There is a new log selector called sender_verify_fail, which is set by - default. If it is unset, the separate log line that gives details of a - sender verification failure is not written. Log lines for the rejection - of SMTP commands (e.g. RCPT) contain just "sender verify failed", so some - detail is lost. - -PH/08 The default for dns_check_names_pattern now allows slashes within names, - as there are now some PTR records that contain slashes. This check is - only to protect against broken name servers that fall over on strange - characters, so the fact that it applies to all lookups doesn't matter. - -PH/09 The default for rfc4131_query_timeout has been changed from 30s to 5s. - -PH/10 When compiled on FreeBSD, NetBSD, or BSD/OS, the pipe transport has a new - Boolean option called use_classresources, defaulting false. If it is set - true, the setclassresources() function is used to set resource limits - when a pipe transport is run to perform a delivery. The limits for the - uid under which the pipe is to run are obtained from the login class - database. - -PH/11 If retry_interval_max is set greater than 24 hours, it is quietly reset - to 24 hours. This avoids potential overflow problems when processing G - and H retry rules, and it seems reasonable to require a retry at least - once a day. - -PH/12 When the plaintext authenticator is running as a client, the server - challenges are now checked to ensure they are valid base64 strings. The - default action on failure is to abort the authentication. However, if - client_ignore_invalid_base64 is set true, invalid responses are ignored. - -PH/13 When the plaintext authenticator is running as a client, the challenges - from the server are placed in $auth1, $auth2, etc. as they are received. - Thus, the challege that is received in response to sending the first - string (with the AUTH command) can be used in the expansion of the second - string, and so on. Currently, up to 3 challenge strings are available in - this way. If an invalid base64 string is received when client_ignore_ - invalid_base64 is set, an empty string is put in the $auth variable. +The documentation is up-to-date for the 4.61 release. Major new features since +the 4.60 release are: + +. An option called disable_ipv6, to disable the use of IPv6 completely. + +. An increase in the number of ACL variables to 20 of each type. + +. A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1, + $2, $3, (though those are still set) because the numeric variables get used + for other things in complicated expansions. + +. The default for rfc1413_query_timeout has been changed from 30s to 5s. + +. It is possible to use setclassresources() on some BSD OS to control the + resources used in pipe deliveries. + +. A new ACL modifier called add_header, which can be used with any verb. + +. More errors are detectable in retry rules. + +There are a number of other additions too. Version 4.60