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diff --git a/README.UPDATING b/README.UPDATING new file mode 100644 index 0000000..72bc970 --- /dev/null +++ b/README.UPDATING @@ -0,0 +1,885 @@ +This document contains detailed information about incompatibilities that might +be encountered when upgrading from one release of Exim to another. The +information is in reverse order of release numbers. Mostly these are relatively +small points, and the configuration file is normally upwards compatible, but +there have been two big upheavals... + + +************************************************************************** +* There was a big reworking of the way mail routing works for release * +* 4.00. Previously used "directors" were abolished, and all routing is * +* now done by routers. Policy controls for incoming mail are now done by * +* Access Control Lists instead of separate options. All this means that * +* pre-4.00 configuration files have to be massively converted. If you * +* are coming from a 3.xx release, please read the document in the file * +* doc/Exim4.upgrade, and allow some time to complete the upgrade. * +* * +* There was a big reworking of the way domain/host/net/address lists are * +* handled at release 3.00. If you are coming from a pre-3.00 release, it * +* might be easier to start again from a default configuration. Otherwise * +* you need to read doc/Exim3.upgrade and do a double conversion of your * +* configuration file. * +************************************************************************** + + +The rest of this document contains information about changes in 4.xx releases +that might affect a running system. + + +Exim version 4.95 +----------------- + +Various length limits have been applied to Exim's parsing of its command-line. +These are all set to be at least as long as any valid input, so we do not believe +that any real use-cases have been affected by this. + +The names of various drivers (authenticators, routers, transports, ...) have +always been limited to 64 characters, but before this release the names were +silently truncated, inviting problems. Now the length limit should be enforced. +If this affects you, then please rename to use shorter names. + +The default maximum number of recipients of a single email has changed from +"unlimited" (ie: as much as CPU and memory will allow, until something breaks +badly) to 50,000. You can raise or lower this as you see fit, but we strongly +caution against using zero/unlimited. + + +Exim version 4.94 +----------------- + +Some Transports now refuse to use tainted data in constructing their delivery +location; this WILL BREAK configurations which are not updated accordingly. +In particular: any Transport use of $local_part which has been relying upon +check_local_user far away in the Router to make it safe, should be updated to +replace $local_part with $local_part_data. + +Attempting to remove, in router or transport, a header name that ends with +an asterisk (which is a standards-legal name) will now result in all headers +named starting with the string before the asterisk being removed. We recommend +staying away from such names, if they are private ones (and in case of future +enhancements, alao header names that look like REs). + + +Exim version 4.93 +----------------- + +For a detailed list of changes that might affect Exim's operation with +an unchanged configuration, please see the doc/ChangeLog file. + +Build: + + * SUPPORT_DMARC replaces EXPERIMENTAL_DMARC + + * DISABLE_TLS replaces SUPPORT_TLS + + * Bump the version for the local_scan API. + +Runtime: + + * smtp transport option hosts_try_fastopen defaults to "*". + + * DNSSec is requested (not required) for all queries. (This seemes to + ask for trouble if your resolver is a systemd-resolved.) + + * Generic router option retry_use_local_part defaults to "true" under specific + pre-conditions. + + * Introduce a tainting mechanism for values read from untrusted sources. + + * Use longer file names for temporary spool files (this avoids + name conflicts with spool on a shared file system). + + * Use dsn_from main config option (was ignored previously). + + +Exim version 4.92 +----------------- + + * Exim used to manually follow CNAME chains, to a limited depth. In this + day-and-age we expect the resolver to be doing this for us, so the loop + is limited to one retry unless the (new) config option dns_cname_loops + is changed. + +Exim version 4.91 +----------------- + + * DANE and SPF have been promoted from Experimental to Supported status, thus + the options to enable them in Local/Makefile have been renamed. + See current src/EDITME for full details, including changes in dependencies, + but loosely: replace EXPERIMENTAL_SPF with SUPPORT_SPF and replace + EXPERIMENTAL_DANE with SUPPORT_DANE. + + * Ancient ClamAV stream support, long deprecated by ClamAV, has been removed; + if you were building with WITH_OLD_CLAMAV_STREAM enabled then your problems + have marginally increased. + + * A number of logging changes; if relying upon the previous DKIM additional + log-line, explicit log_selector configuration is needed to keep it. + + * Other incompatible changes in EXPERIMENTAL_* features, read NewStuff and + ChangeLog carefully if relying upon an experimental feature such as DMARC. + Note that this includes changes to SPF as it was promoted into Supported. + + +Exim version 4.89 +----------------- + + * SMTP CHUNKING in Exim 4.88 did not ensure that received mails had a final + newline; attempts to deliver such messages onwards to non-chunking hosts + would probably hang, as Exim does not insert the newline before a ".". + In 4.89, the newline is added upon receipt. For already-received messages + in your queue, try util/chunking_fixqueue_finalnewlines.pl + to walk the queue, fixing any affected messages. Note that because a + delivery attempt will be hanging, attempts to lock the messages for fixing + them will stall; stopping all queue-runners temporarily is recommended. + + * OpenSSL: oldest supported release series is now 1.0.2, which is the oldest + supported by the OpenSSL project. If you can build Exim with an older + release series, congratulations. If you can't, then upgrade. + The file doc/openssl.txt contains instructions for installing a current + OpenSSL outside the system library paths and building Exim to use it. + + * FreeBSD: we now always use the system iconv in libc, as all versions of + FreeBSD supported by the FreeBSD project provide this functionality. + + +Exim version 4.88 +----------------- + + * The "demime" ACL condition, deprecated for the past 10 years, has + now been removed. + + * Old GnuTLS configuration options "gnutls_require_kx", "gnutls_require_mac", + and "gnutls_require_protocols" have now been removed. (Inoperative from + 4.80, per below; logging warnings since 4.83, again per below). + + +Exim version 4.83 +----------------- + + * SPF condition results renamed "permerror" and "temperror". The old + names are still accepted for back-compatibility, for this release. + + * TLS details are now logged on rejects, subject to log selectors. + + * Items in headers_remove lists must now have any embedded list-separators + doubled. + + * Attempted use of the deprecated options "gnutls_require_kx" et. al. + now result in logged warning. + + +Exim version 4.82 +----------------- + + * New option gnutls_allow_auto_pkcs11 defaults false; if you have GnuTLS 2.12.0 + or later and do want PKCS11 modules to be autoloaded, then set this option. + + * A per-transport wait-<name> database is no longer updated if the transport + sets "connection_max_messages" to 1, as it can not be used and causes + unnecessary serialisation and load. External tools tracking the state of + Exim by the hints databases may need modification to take this into account. + + * The av_scanner option can now accept multiple clamd TCP targets, all other + setting limitations remain. + + +Exim version 4.80 +----------------- + + * BEWARE backwards-incompatible changes in SSL libraries, thus the version + bump. See points below for details. + Also an LDAP data returned format change. + + * The value of $tls_peerdn is now print-escaped when written to the spool file + in a -tls_peerdn line, and unescaped when read back in. We received reports + of values with embedded newlines, which caused spool file corruption. + + If you have a corrupt spool file and you wish to recover the contents after + upgrading, then lock the message, replace the new-lines that should be part + of the -tls_peerdn line with the two-character sequence \n and then unlock + the message. No tool has been provided as we believe this is a rare + occurrence. + + * For OpenSSL, SSLv2 is now disabled by default. (GnuTLS does not support + SSLv2). RFC 6176 prohibits SSLv2 and some informal surveys suggest no + actual usage. You can re-enable with the "openssl_options" Exim option, + in the main configuration section. Note that supporting SSLv2 exposes + you to ciphersuite downgrade attacks. + + * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built + against 1.0.1a then you will get a warning message and the + "openssl_options" value will not parse "no_tlsv1_1": the value changes + incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a + is infelicitous. We advise avoiding 1.0.1a. + + "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression". + + COMPATIBILITY WARNING: The default value of "openssl_options" is no longer + "+dont_insert_empty_fragments". We default to "+no_sslv2". + That old default was grandfathered in from before openssl_options became a + configuration option. + Empty fragments are inserted by default through TLS1.0, to partially defend + against certain attacks; TLS1.1+ change the protocol so that this is not + needed. The DIEF SSL option was required for some old releases of mail + clients which did not gracefully handle the empty fragments, and was + initially set in Exim release 4.31 (see ChangeLog, item 37). + + If you still have affected mail-clients, and you see SSL protocol failures + with this release of Exim, set: + openssl_options = +dont_insert_empty_fragments + in the main section of your Exim configuration file. You're trading off + security for compatibility. Exim is now defaulting to higher security and + rewarding more modern clients. + + If the option tls_dhparams is set and the parameters loaded from the file + have a bit-count greater than the new option tls_dh_max_bits, then the file + will now be ignored. If this affects you, raise the tls_dh_max_bits limit. + We suspect that most folks are using dated defaults and will not be affected. + + * Ldap lookups returning multi-valued attributes now separate the attributes + with only a comma, not a comma-space sequence. Also, an actual comma within + a returned attribute is doubled. This makes it possible to parse the + attribute as a comma-separated list. Note the distinction from multiple + attributes being returned, where each one is a name=value pair. + + If you are currently splitting the results from LDAP upon a comma, then you + should check carefully to see if adjustments are needed. + + This change lets cautious folks distinguish "comma used as separator for + joining values" from "comma inside the data". + + * accept_8bitmime now defaults on, which is not RFC compliant but is better + suited to today's Internet. See http://cr.yp.to/smtp/8bitmime.html for a + sane rationale. Those who wish to be strictly RFC compliant, or know that + they need to talk to servers that are not 8-bit-clean, now need to take + explicit configuration action to default this option off. This is not a + new option, you can safely force it off before upgrading, to decouple + configuration changes from the binary upgrade while remaining RFC compliant. + + * The GnuTLS support has been mostly rewritten, to use APIs which don't cause + deprecation warnings in GnuTLS 2.12.x. As part of this, these three options + are no longer supported: + + gnutls_require_kx + gnutls_require_mac + gnutls_require_protocols + + Their functionality is entirely subsumed into tls_require_ciphers. In turn, + tls_require_ciphers is no longer an Exim list and is not parsed by Exim, but + is instead given to gnutls_priority_init(3), which expects a priority string; + this behaviour is much closer to the OpenSSL behaviour. See: + + http://www.gnutls.org/manual/html_node/Priority-Strings.html + + for fuller documentation of the strings parsed. The three gnutls_require_* + options are still parsed by Exim and, for this release, silently ignored. + A future release will add warnings, before a later still release removes + parsing entirely and the presence of the options will be a configuration + error. + + Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains. + A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may + re-enable support, but this is not supported by the Exim maintainers. + Our test suite no longer includes MD5-based certificates. + + This rewrite means that Exim will continue to build against GnuTLS in the + future, brings Exim closer to other GnuTLS applications and lets us add + support for SNI and other features more readily. We regret that it wasn't + feasible to retain the three dropped options. + + * If built with TLS support, then Exim will now validate the value of + the main section tls_require_ciphers option at start-up. Before, this + would cause a STARTTLS 4xx failure, now it causes a failure to start. + Running with a broken configuration which causes failures that may only + be left in the logs has been traded off for something more visible. This + change makes an existing problem more prominent, but we do not believe + anyone would deliberately be running with an invalid tls_require_ciphers + option. + + This also means that library linkage issues caused by conflicts of some + kind might take out the main daemon, not just the delivery or receiving + process. Conceivably some folks might prefer to continue delivering + mail plaintext when their binary is broken in this way, if there is a + server that is a candidate to receive such mails that does not advertise + STARTTLS. Note that Exim is typically a setuid root binary and given + broken linkage problems that cause segfaults, we feel it is safer to + fail completely. (The check is not done as root, to ensure that problems + here are not made worse by the check). + + * The "tls_dhparam" option has been updated, so that it can now specify a + path or an identifier for a standard DH prime from one of a few RFCs. + The default for OpenSSL is no longer to not use DH but instead to use + one of these standard primes. The default for GnuTLS is no longer to use + a file in the spool directory, but to use that same standard prime. + The option is now used by GnuTLS too. If it points to a path, then + GnuTLS will use that path, instead of a file in the spool directory; + GnuTLS will attempt to create it if it does not exist. + + To preserve the previous behaviour of generating files in the spool + directory, set "tls_dhparam = historic". Since prior releases of Exim + ignored tls_dhparam when using GnuTLS, this can safely be done before + the upgrade. + + + +Exim version 4.77 +----------------- + + * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3, + if supported by your GnuTLS library. Use the existing + "gnutls_require_protocols" option to downgrade this if that will be a + problem. Prior to this release, supported values were "TLS1" and "SSL3", + so you should be able to update configuration prior to update. + + [nb: gnutls_require_protocols removed in Exim 4.80, instead use + tls_require_ciphers to provide a priority string; see notes above] + + * The match_<type>{string1}{string2} expansion conditions no longer subject + string2 to string expansion, unless Exim was built with the new + "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created + insecure configurations that way. If you need the functionality and turn on + that build option, please let the developers know, and know why, so we can + try to provide a safer mechanism for you. + + The match{}{} expansion condition (for regular expressions) is NOT affected. + For match_<type>{s1}{s2}, all list functionality is unchanged. The only + change is that a '$' appearing in s2 will not trigger expansion, but instead + will be treated as a literal $ sign; the effect is very similar to having + wrapped s2 with \N...\N. If s2 contains a named list and the list definition + uses $expansions then those _will_ be processed as normal. It is only the + point at which s2 is read where expansion is inhibited. + + If you are trying to test if two email addresses are equal, use eqi{s1}{s2}. + If you are testing if the address in s1 occurs in the list of items given + in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use + the pre-existing forany{s2}{eqi{$item}{s1}} condition. + + +Exim version 4.74 +----------------- + + * The integrated support for dynamically loadable lookup modules has an ABI + change from the modules supported by some OS vendors through an unofficial + patch. Don't try to mix & match. + + * Some parts of the build system are now beginning to assume that the host + environment is POSIX. If you're building on a system where POSIX tools are + not the default, you might have an easier time if you switch to the POSIX + tools. Feel free to report non-POSIX issues as a request for a feature + enhancement, but if the POSIX variants are available then the fix will + probably just involve some coercion. See the README instructions for + building on such hosts. + + +Exim version 4.73 +----------------- + + * The Exim run-time user can no longer be root; this was always + strongly discouraged, but is now prohibited both at build and + run-time. If you need Exim to run routinely as root, you'll need to + patch the source and accept the risk. Here be dragons. + + * Exim will no longer accept a configuration file owned by the Exim + run-time user, unless that account is explicitly the value in + CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that + files are not writeable by other accounts. + + * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced + on; the Exim user can, by default, no longer use -C/-D and retain privilege. + Two new build options mitigate this. + + * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config + files that are trusted to be selected by the Exim user; one per line. + This is the recommended approach going forward. + + * WHITELIST_D_MACROS defines a colon-separated list of macro names which + the Exim run-time user may safely pass without dropping privileges. + Because changes to this involve a recompile, this is not the recommended + approach but may ease transition. The values of the macros, when + overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$ + + * The system_filter_user option now defaults to the Exim run-time user, + rather than root. You can still set it explicitly to root and this + can be done with prior versions too, letting you roll versions + without needing to change this configuration option. + + * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is + defined at build time. + + +Exim version 4.70 +----------------- + +1. Experimental Yahoo! Domainkeys support has been dropped in this release. +It has been superseded by a native implementation of its successor DKIM. + +2. Up to version 4.69, Exim came with an embedded version of the PCRE library. +As of 4.70, this is no longer the case. To compile Exim, you will need PCRE +installed. Most OS distributions have ready-made library and development +packages. + + +Exim version 4.68 +----------------- + +1. The internal implementation of the database keys that are used for ACL +ratelimiting has been tidied up. This means that an update to 4.68 might cause +Exim to "forget" previous rates that it had calculated, and reset them to zero. + + +Exim version 4.64 +----------------- + +1. Callouts were setting the name used for EHLO/HELO from $smtp_active_ +hostname. This is wrong, because it relates to the incoming message (and +probably the interface on which it is arriving) and not to the outgoing +callout (which could be using a different interface). This has been +changed to use the value of the helo_data option from the smtp transport +instead - this is what is used when a message is actually being sent. If +there is no remote transport (possible with a router that sets up host +addresses), $smtp_active_hostname is used. This change is mentioned here in +case somebody is relying on the use of $smtp_active_hostname. + +2. A bug has been fixed that might just possibly be something that is relied on +in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an +empty string (that is {}) was being interpreted as if it was {0} and therefore +treated as the number zero. From release 4.64, such strings cause an error +because a decimal number, possibly followed by K or M, is required (as has +always been documented). + +3. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve +Exim's performance. Unfortunately, this has the side effect of being slightly +non-upwards compatible for versions 4.50 and earlier. If you are upgrading from +one of these earlier versions and you use GnuTLS, you must remove the file +called gnutls-params in Exim's spool directory. If you don't do this, you will +see this error: + + TLS error on connection from ... (DH params import): Base64 decoding error. + +Removing the file causes Exim to recompute the relevant encryption parameters +and cache them in the new format that was introduced for release 4.51 (May +2005). If you are upgrading from release 4.51 or later, there should be no +problem. + + +Exim version 4.63 +----------------- + +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. This consists of three digits followed +by a space, optionally followed by an extended code of the form n.n.n, also +followed by a space. If this is the case and the very first digit is the same +as the default error code, the code from the message is used instead. If the +very first digit is incorrect, a panic error is logged, and the default code is +used. This is an incompatible change, but it is not expected to affect many (if +any) configurations. It is possible to suppress the use of the supplied code in +a redirect router by setting the smtp_error_code option false. In this case, +any SMTP code is quietly ignored. + + +Exim version 4.61 +----------------- + +1. The default number of ACL variables of each type has been increased to 20, +and it's possible to compile Exim with more. You can safely upgrade to this +release if you already have messages on the queue with saved ACL variable +values. However, if you downgrade from this release with messages on the queue, +any saved ACL values they may have will be lost. + +2. The default value for rfc1413_query_timeout has been changed from 30s to 5s. + + +Exim version 4.54 +----------------- + +There was a problem with 4.52/TF/02 in that a "name=" option on control= +submission terminated at the next slash, thereby not allowing for slashes in +the name. This has been changed so that "name=" takes the rest of the string as +its data. It must therefore be the last option. + + +Version 4.53 +------------ + +If you are using the experimental Domain Keys support, you must upgrade to +at least libdomainkeys 0.67 in order to run this release of Exim. + + +Version 4.51 +------------ + +1. The format in which GnuTLS parameters are cached (in the file gnutls-params +in the spool directory) has been changed. The new format can also be generated +externally, so it is now possible to update the values from outside Exim. This +has been implemented in an upwards, BUT NOT downwards, compatible manner. +Upgrading should be seamless: when Exim finds that it cannot understand an +existing cache file, it generates new parameters and writes them to the cache +in the new format. If, however, you downgrade from 4.51 to a previous release, +you MUST delete the gnutls-params file in the spool directory, because the +older Exim will not recognize the new format. + +2. When doing a callout as part of verifying an address, Exim was not paying +attention to any local part prefix or suffix that was matched by the router +that accepted the address. It now behaves in the same way as it does for +delivery: the affixes are removed from the local part unless +rcpt_include_affixes is set on the transport. If you have a configuration that +uses prefixes or suffixes on addresses that could be used for callouts, and you +want the affixes to be retained, you must make sure that rcpt_include_affixes +is set on the transport. + +3. Bounce and delay warning messages no longer contain details of delivery +errors, except for explicit messages (e.g. generated by :fail:) and SMTP +responses from remote hosts. + + +Version 4.50 +------------ + +The exicyclog script has been updated to use three-digit numbers in rotated log +files if the maximum number to keep is greater than 99. If you are already +keeping more than 99, there will be an incompatible change when you upgrade. +You will probably want to rename your old log files to the new form before +running the new exicyclog. + + +Version 4.42 +------------ + +RFC 3848 specifies standard names for the "with" phrase in Received: header +lines when AUTH and/or TLS are in use. This is the "received protocol" +field. Exim used to use "asmtp" for authenticated SMTP, without any +indication (in the protocol name) for TLS use. Now it follows the RFC and +uses "esmtpa" if the connection is authenticated, "esmtps" if it is +encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names +appear in log lines as well as in Received: header lines. + + +Version 4.34 +------------ + +Change 4.31/2 gave problems to data ACLs and local_scan() functions that +expected to see a Received: header. I have changed to yet another scheme. The +Received: header is now generated after the body is received, but before the +ACL or local_scan() is called. After they have run, the timestamp in the +Received: header is updated. + +Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true, +which is lucky, since I decided it was a bug fix. + + +Version 4.33 +------------ + +If an expansion in a condition on a "warn" statement fails because a lookup +defers, the "warn" statement is abandoned, and the next ACL statement is +processed. Previously this caused the whole ACL to be aborted. + + +Version 4.32 +------------ + +Change 4.31/2 has been reversed, as it proved contentious. Recipient callout +verification now uses <> in the MAIL command by default, as it did before. A +new callout option, "use_sender", has been added to request the other +behaviour. + + +Version 4.31 +------------ + +1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0 + or greater. The interface to the obsolete 0.8.x releases is no longer + supported. There is one externally visible change: the format for the + display of Distinguished Names now uses commas as a separator rather than a + slash. This is to comply with RFC 2253. + +2. When a message is received, the Received: header line is now generated when + reception is complete, instead of at the start of reception. For messages + that take a long time to come in, this changes the meaning of the timestamp. + There are several side-effects of this change: + + (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(), + the logged header lines no longer include the local Received: line, + because it has not yet been created. If the message is a non-SMTP one, + and the error is processed by sending a message to the sender, the copy + of the original message that is returned does not have an added + Received: line. + + (b) When a filter file is tested using -bf, no additional Received: header + is added to the test message. After some thought, I decided that this + is a bug fix. + + The contents of $received_for are not affected by this change. This + variable still contains the single recipient of a message, copied after + addresses have been rewritten, but before local_scan() is run. + +2. Recipient callout verification, like sender verification, was using <> in + the MAIL FROM command. This isn't really the right thing, since the actual + sender may affect whether the remote host accepts the recipient or not. I + have changed it to use the actual sender in the callout; this means that + the cache record is now keyed on a recipient/sender pair, not just the + recipient address. There doesn't seem to be a real danger of callout loops, + since a callout by the remote host to check the sender would use <>. + + +Version 4.30 +------------ + +1. I have abolished timeout_DNS as an error that can be detected in retry + rules, because it has never worked. Despite the fact that it has been + documented since at least release 1.62, there was no code to support it. + If you have used it in your retry rules, you will now get a warning message + to the log and panic log. It is now treated as plain "timeout". + +2. After discussion on the mailing list, Exim no longer adds From:, Date:, or + Message-Id: header lines to messages that do not originate locally, that is, + messages that have an associated sending host address. + +3. When looking up a host name from an IP address, Exim now tries the DNS + first, and only if that fails does it use gethostbyaddr() (or equivalent). + This change was made because on some OS, not all the names are given for + addresses with multiple PTR records via the gethostbyaddr() interface. The + order of lookup can be changed by setting host_lookup_order. + + +Version 4.23 +------------ + +1. The new FIXED_NEVER_USERS build-time option creates a list of "never users" + that cannot be overridden. The default in the distributed EDITME is "root". + If for some reason you were (against advice) running deliveries as root, you + will have to ensure that FIXED_NEVER_USERS is not set in your + Local/Makefile. + +2. The ${quote: operator now quotes an empty string, which it did not before. + +3. Version 4.23 saves the contents of the ACL variables with the message, so + that they can be used later. If one of these variables contains a newline, + there will be a newline character in the spool that will not be interpreted + correctly by a previous version of Exim. (Exim ignores keyed spool file + items that it doesn't understand - precisely for this kind of problem - but + it expects them all to be on one line.) + + So the bottom line is: if you have newlines in your ACL variables, you + cannot retreat from 4.23. + + +Version 4.21 +------------ + +1. The idea of the "warn" ACL verb is that it adds a header or writes to the + log only when "message" or "log_message" are set. However, if one of the + conditions was an address verification, or a call to a nested ACL, the + messages generated by the underlying test were being passed through. This + no longer happens. The underlying message is available in $acl_verify_ + message for both "message" and "log_message" expansions, so it can be + passed through if needed. + +2. The way that the $h_ (and $header_) expansions work has been changed by the + addition of RFC 2047 decoding. See the main documentation (the NewStuff file + until release 4.30, then the manual) for full details. Briefly, there are + now three forms: + + $rh_xxx: and $rheader_xxx: give the original content of the header + line(s), with no processing at all. + + $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and + then decode base64 or quoted-printable "words" within the header text, + but do not do charset translation. + + $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a + standard character set. + + If you have previously been using $h_ expansions to access the raw + characters, you should change to $rh_ instead. + +3. When Exim creates an RFC 2047 encoded word in a header line, it labels it + with the default character set from the headers_charset option instead of + always using iso-8859-1. + +4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is + TMPDIR="/tmp"), Exim checks for the presence of an environment variable + called TMPDIR, and if it finds it is different, it changes its value. + +5. Following a discussion on the list, the rules by which Exim recognises line + endings on incoming messages have been changed. The -dropcr and drop_cr + options are now no-ops, retained only for backwards compatibility. The + following line terminators are recognized: LF CRLF CR. However, special + processing applies to CR: + + (i) The sequence CR . CR does *not* terminate an incoming SMTP message, + nor a local message in the state where . is a terminator. + + (ii) If a bare CR is encountered in a header line, an extra space is added + after the line terminator so as not to end the header. The reasoning + behind this is that bare CRs in header lines are most likely either + to be mistakes, or people trying to play silly games. + +6. The code for using daemon_smtp_port, local_interfaces, and the -oX options + has been reorganized. It is supposed to be backwards compatible, but it is + mentioned here just in case I've screwed up. + + + +Version 4.20 +------------ + +1. I have tidied and re-organized the code that uses alarm() for imposing time + limits on various things. It shouldn't affect anything, but if you notice + processes getting stuck, it may be that I've broken something. + +2. The "arguments" log selector now also logs the current working directory + when Exim is called. + +3. An incompatible change has been made to the appendfile transport. This + affects the case when it is used for file deliveries that are set up by + .forward and filter files. Previously, any settings of the "file" or + "directory" options were ignored. It is hoped that, like the address_file + transport in the default configuration, these options were never in fact set + on such transports, because they were of no use. + + Now, if either of these options is set, it is used. The path that is passed + by the router is in $address_file (this is not new), so it can be used as + part of a longer path, or modified in any other way that expansion permits. + + If neither "file" nor "directory" is set, the behaviour is unchanged. + +4. Related to the above: in a filter, if a "save" command specifies a non- + absolute path, the value of $home/ is pre-pended. This no longer happens if + $home is unset or is set to an empty string. + +5. Multiple file deliveries from a filter or .forward file can never be + batched; the value of batch_max on the transport is ignored for file + deliveries. I'm assuming that nobody ever actually set batch_max on the + address_file transport - it would have had odd effects previously. + +6. DESTDIR is the more common variable that ROOT for use when installing + software under a different root filing system. The Exim install script now + recognizes DESTDIR first; if it is not set, ROOT is used. + +7. If DESTDIR is set when installing Exim, it no longer prepends its value to + the path of the system aliases file that appears in the default + configuration (when a default configuration is installed). If an aliases + file is actually created, its name *does* use the prefix. + + +Version 4.14 +------------ + +1. The default for the maximum number of unknown SMTP commands that Exim will +accept before dropping a connection has been reduced from 5 to 3. However, you +can now change the value by setting smtp_max_unknown_commands. + +2. The ${quote: operator has been changed so that it turns newline and carriage +return characters into \n and \r, respectively. + +3. The file names used for maildir messages now include the microsecond time +fraction as well as the time in seconds, to cope with systems where the process +id can be re-used within the same second. The format is now + + <time>.H<microsec>P<pid>.<host> + +This should be a compatible change, but is noted here just in case. + +4. The rules for creating message ids have changed, to cope with systems where +the process id can be re-used within the same second. The format, however, is +unchanged, so this should not cause any problems, except as noted in the next +item. + +5. The maximum value for localhost_number has been reduced from 255 to 16, in +order to implement the new message id rules. For operating systems that have +case-insensitive file systems (Cygwin and Darwin), the limit is 10. + +6. verify = header_syntax was allowing unqualified addresses in all cases. Now +it allows them only for locally generated messages and from hosts that match +sender_unqualified_hosts or recipient_unqualified_hosts, respectively. + +7. For reasons lost in the mists of time, when a pipe transport was run, the +environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the +form used in Message-ID: header lines). The 'E' has been removed. + + +Version 4.11 +------------ + +1. The handling of lines in the configuration file has changed. Previously, +macro expansion was applied to logical lines, after continuations had been +joined on. This meant that it could not be used in .include lines, which are +handled as physical rather than logical lines. Macro expansion is now done on +physical lines rather than logical lines. This means there are two +incompatibilities: + + (a) A macro that expands to # to turn a line into a comment now applies only + to the physical line where it appears. Previously, it would have caused + any following continuations also to be ignored. + + (b) A macro name can no longer be split over the boundary between a line and + its continuation. Actually, this is more of a bug fix. :-) + +2. The -D command line option must now all be within one command line item. +This makes it possible to use -D to set a macro to the empty string by commands +such as + + exim -DABC ... + exim -DABC= ... + +Previously, these items would have moved on to the next item on the command +line. To include spaces in a macro definition item, quotes must be used, in +which case you can also have spaces after -D and surrounding the equals. For +example: + + exim '-D ABC = something' ... + +3. The way that addresses that redirect to themselves are handled has been +changed, in order to fix an obscure bug. This should not cause any problems +except in the case of wanting to go back from a 4.11 (or later) release to an +earlier release. If there are undelivered messages on the spool that contain +addresses which redirect to themselves, and the redirected addresses have +already been delivered, you might get a duplicate delivery if you revert to an +earlier Exim. + +4. The default way of looking up IP addresses for hosts in the manualroute and +queryprogram routers has been changed. If "byname" or "bydns" is explicitly +specified, there is no change, but if no method is specified, Exim now behaves +as follows: + + First, a DNS lookup is done. If this yields anything other than + HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to + getipnodebyname() (or gethostbyname() on older systems) and the result of the + lookup is the result of that call. + +This change has been made because it has been discovered that on some systems, +if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is +returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly +first, and only if that gives a definite "no such host" to try the local +function. + +5. In fixing the minor security problem with pid_file_path, I have removed some +backwards-compatible (undocumented) code which was present to ease conversion +from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to +contain "%s", which was replaced by the port number for daemons listening on +non-standard ports. In Exim 4, such daemons do not write a pid file. The +backwards compatibility feature was to replace "%s" by nothing if it occurred +in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved +the problem by removing the backwards compatibility feature. Thus, if you still +have "%s" somewhere in a setting of pid_file_path, you should remove it. + +6. There has been an extension to lsearch files. The keys in these files may +now be quoted in order to allow for whitespace and colons in them. This means +that if you were previously using keys that began with a doublequote, you will +now have to wrap them with extra quotes and escape the internal quotes. The +possibility that anybody is actually doing this seems extremely remote, but it +is documented just in case. + + +Version 4.10 +------------ + +The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL +to better reflect its function. The OS-specific files have been updated. Only +if you have explicitly set this in your Makefile (highly unlikely) do you need +to change anything. + +**** |