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 4.80 ----------------- * BEWARE backwards-incompatible changes in SSL libraries, thus the version bump. See points below for details. * 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 occurence. * 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 unset. 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. * 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. * 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 2.12.x APIs. 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, which is no longer parsed apart by Exim but is instead given to gnutls_priority_init(3), which is no longer an Exim list. See: http://www.gnu.org/software/gnutls/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. 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_{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_{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 superceded 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 correctely 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