1 This document contains detailed information about incompatibilities that might
2 be encountered when upgrading from one release of Exim to another. The
3 information is in reverse order of release numbers. Mostly these are relatively
4 small points, and the configuration file is normally upwards compatible, but
5 there have been two big upheavals...
8 **************************************************************************
9 * There was a big reworking of the way mail routing works for release *
10 * 4.00. Previously used "directors" were abolished, and all routing is *
11 * now done by routers. Policy controls for incoming mail are now done by *
12 * Access Control Lists instead of separate options. All this means that *
13 * pre-4.00 configuration files have to be massively converted. If you *
14 * are coming from a 3.xx release, please read the document in the file *
15 * doc/Exim4.upgrade, and allow some time to complete the upgrade. *
17 * There was a big reworking of the way domain/host/net/address lists are *
18 * handled at release 3.00. If you are coming from a pre-3.00 release, it *
19 * might be easier to start again from a default configuration. Otherwise *
20 * you need to read doc/Exim3.upgrade and do a double conversion of your *
21 * configuration file. *
22 **************************************************************************
25 The rest of this document contains information about changes in 4.xx releases
26 that might affect a running system.
31 For a detailed list of changes that might affect Exim's operation with
32 an unchanged configuration, please see the doc/ChangeLog file.
36 * SUPPORT_DMARC replaces EXPERIMENTAL_DMARC
38 * DISABLE_TLS replaces SUPPORT_TLS
40 * Bump the version for the local_scan API.
44 * smtp transport option hosts_try_fastopen defaults to "*".
46 * DNSSec is requested (not required) for all queries. (This seemes to
47 ask for trouble if your resolver is a systemd-resolved.)
49 * Generic router option retry_use_local_part defaults to "true" under specific
52 * Introduce a tainting mechanism for values read from untrusted sources.
54 * Use longer file names for temporary spool files (this avoids
55 name conflicts with spool on a shared file system).
57 * Use dsn_from main config option (was ignored previously).
63 * Exim used to manually follow CNAME chains, to a limited depth. In this
64 day-and-age we expect the resolver to be doing this for us, so the loop
65 is limited to one retry unless the (new) config option dns_cname_loops
71 * DANE and SPF have been promoted from Experimental to Supported status, thus
72 the options to enable them in Local/Makefile have been renamed.
73 See current src/EDITME for full details, including changes in dependencies,
74 but loosely: replace EXPERIMENTAL_SPF with SUPPORT_SPF and replace
75 EXPERIMENTAL_DANE with SUPPORT_DANE.
77 * Ancient ClamAV stream support, long deprecated by ClamAV, has been removed;
78 if you were building with WITH_OLD_CLAMAV_STREAM enabled then your problems
79 have marginally increased.
81 * A number of logging changes; if relying upon the previous DKIM additional
82 log-line, explicit log_selector configuration is needed to keep it.
84 * Other incompatible changes in EXPERIMENTAL_* features, read NewStuff and
85 ChangeLog carefully if relying upon an experimental feature such as DMARC.
86 Note that this includes changes to SPF as it was promoted into Supported.
92 * SMTP CHUNKING in Exim 4.88 did not ensure that received mails had a final
93 newline; attempts to deliver such messages onwards to non-chunking hosts
94 would probably hang, as Exim does not insert the newline before a ".".
95 In 4.89, the newline is added upon receipt. For already-received messages
96 in your queue, try util/chunking_fixqueue_finalnewlines.pl
97 to walk the queue, fixing any affected messages. Note that because a
98 delivery attempt will be hanging, attempts to lock the messages for fixing
99 them will stall; stopping all queue-runners temporarily is recommended.
101 * OpenSSL: oldest supported release series is now 1.0.2, which is the oldest
102 supported by the OpenSSL project. If you can build Exim with an older
103 release series, congratulations. If you can't, then upgrade.
104 The file doc/openssl.txt contains instructions for installing a current
105 OpenSSL outside the system library paths and building Exim to use it.
107 * FreeBSD: we now always use the system iconv in libc, as all versions of
108 FreeBSD supported by the FreeBSD project provide this functionality.
114 * The "demime" ACL condition, deprecated for the past 10 years, has
117 * Old GnuTLS configuration options "gnutls_require_kx", "gnutls_require_mac",
118 and "gnutls_require_protocols" have now been removed. (Inoperative from
119 4.80, per below; logging warnings since 4.83, again per below).
125 * SPF condition results renamed "permerror" and "temperror". The old
126 names are still accepted for back-compatibility, for this release.
128 * TLS details are now logged on rejects, subject to log selectors.
130 * Items in headers_remove lists must now have any embedded list-separators
133 * Attempted use of the deprecated options "gnutls_require_kx" et. al.
134 now result in logged warning.
140 * New option gnutls_allow_auto_pkcs11 defaults false; if you have GnuTLS 2.12.0
141 or later and do want PKCS11 modules to be autoloaded, then set this option.
143 * A per-transport wait-<name> database is no longer updated if the transport
144 sets "connection_max_messages" to 1, as it can not be used and causes
145 unnecessary serialisation and load. External tools tracking the state of
146 Exim by the hints databases may need modification to take this into account.
148 * The av_scanner option can now accept multiple clamd TCP targets, all other
149 setting limitations remain.
155 * BEWARE backwards-incompatible changes in SSL libraries, thus the version
156 bump. See points below for details.
157 Also an LDAP data returned format change.
159 * The value of $tls_peerdn is now print-escaped when written to the spool file
160 in a -tls_peerdn line, and unescaped when read back in. We received reports
161 of values with embedded newlines, which caused spool file corruption.
163 If you have a corrupt spool file and you wish to recover the contents after
164 upgrading, then lock the message, replace the new-lines that should be part
165 of the -tls_peerdn line with the two-character sequence \n and then unlock
166 the message. No tool has been provided as we believe this is a rare
169 * For OpenSSL, SSLv2 is now disabled by default. (GnuTLS does not support
170 SSLv2). RFC 6176 prohibits SSLv2 and some informal surveys suggest no
171 actual usage. You can re-enable with the "openssl_options" Exim option,
172 in the main configuration section. Note that supporting SSLv2 exposes
173 you to ciphersuite downgrade attacks.
175 * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built
176 against 1.0.1a then you will get a warning message and the
177 "openssl_options" value will not parse "no_tlsv1_1": the value changes
178 incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a
179 is infelicitous. We advise avoiding 1.0.1a.
181 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
183 COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
184 "+dont_insert_empty_fragments". We default to "+no_sslv2".
185 That old default was grandfathered in from before openssl_options became a
186 configuration option.
187 Empty fragments are inserted by default through TLS1.0, to partially defend
188 against certain attacks; TLS1.1+ change the protocol so that this is not
189 needed. The DIEF SSL option was required for some old releases of mail
190 clients which did not gracefully handle the empty fragments, and was
191 initially set in Exim release 4.31 (see ChangeLog, item 37).
193 If you still have affected mail-clients, and you see SSL protocol failures
194 with this release of Exim, set:
195 openssl_options = +dont_insert_empty_fragments
196 in the main section of your Exim configuration file. You're trading off
197 security for compatibility. Exim is now defaulting to higher security and
198 rewarding more modern clients.
200 If the option tls_dhparams is set and the parameters loaded from the file
201 have a bit-count greater than the new option tls_dh_max_bits, then the file
202 will now be ignored. If this affects you, raise the tls_dh_max_bits limit.
203 We suspect that most folks are using dated defaults and will not be affected.
205 * Ldap lookups returning multi-valued attributes now separate the attributes
206 with only a comma, not a comma-space sequence. Also, an actual comma within
207 a returned attribute is doubled. This makes it possible to parse the
208 attribute as a comma-separated list. Note the distinction from multiple
209 attributes being returned, where each one is a name=value pair.
211 If you are currently splitting the results from LDAP upon a comma, then you
212 should check carefully to see if adjustments are needed.
214 This change lets cautious folks distinguish "comma used as separator for
215 joining values" from "comma inside the data".
217 * accept_8bitmime now defaults on, which is not RFC compliant but is better
218 suited to today's Internet. See http://cr.yp.to/smtp/8bitmime.html for a
219 sane rationale. Those who wish to be strictly RFC compliant, or know that
220 they need to talk to servers that are not 8-bit-clean, now need to take
221 explicit configuration action to default this option off. This is not a
222 new option, you can safely force it off before upgrading, to decouple
223 configuration changes from the binary upgrade while remaining RFC compliant.
225 * The GnuTLS support has been mostly rewritten, to use APIs which don't cause
226 deprecation warnings in GnuTLS 2.12.x. As part of this, these three options
227 are no longer supported:
231 gnutls_require_protocols
233 Their functionality is entirely subsumed into tls_require_ciphers. In turn,
234 tls_require_ciphers is no longer an Exim list and is not parsed by Exim, but
235 is instead given to gnutls_priority_init(3), which expects a priority string;
236 this behaviour is much closer to the OpenSSL behaviour. See:
238 http://www.gnutls.org/manual/html_node/Priority-Strings.html
240 for fuller documentation of the strings parsed. The three gnutls_require_*
241 options are still parsed by Exim and, for this release, silently ignored.
242 A future release will add warnings, before a later still release removes
243 parsing entirely and the presence of the options will be a configuration
246 Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains.
247 A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may
248 re-enable support, but this is not supported by the Exim maintainers.
249 Our test suite no longer includes MD5-based certificates.
251 This rewrite means that Exim will continue to build against GnuTLS in the
252 future, brings Exim closer to other GnuTLS applications and lets us add
253 support for SNI and other features more readily. We regret that it wasn't
254 feasible to retain the three dropped options.
256 * If built with TLS support, then Exim will now validate the value of
257 the main section tls_require_ciphers option at start-up. Before, this
258 would cause a STARTTLS 4xx failure, now it causes a failure to start.
259 Running with a broken configuration which causes failures that may only
260 be left in the logs has been traded off for something more visible. This
261 change makes an existing problem more prominent, but we do not believe
262 anyone would deliberately be running with an invalid tls_require_ciphers
265 This also means that library linkage issues caused by conflicts of some
266 kind might take out the main daemon, not just the delivery or receiving
267 process. Conceivably some folks might prefer to continue delivering
268 mail plaintext when their binary is broken in this way, if there is a
269 server that is a candidate to receive such mails that does not advertise
270 STARTTLS. Note that Exim is typically a setuid root binary and given
271 broken linkage problems that cause segfaults, we feel it is safer to
272 fail completely. (The check is not done as root, to ensure that problems
273 here are not made worse by the check).
275 * The "tls_dhparam" option has been updated, so that it can now specify a
276 path or an identifier for a standard DH prime from one of a few RFCs.
277 The default for OpenSSL is no longer to not use DH but instead to use
278 one of these standard primes. The default for GnuTLS is no longer to use
279 a file in the spool directory, but to use that same standard prime.
280 The option is now used by GnuTLS too. If it points to a path, then
281 GnuTLS will use that path, instead of a file in the spool directory;
282 GnuTLS will attempt to create it if it does not exist.
284 To preserve the previous behaviour of generating files in the spool
285 directory, set "tls_dhparam = historic". Since prior releases of Exim
286 ignored tls_dhparam when using GnuTLS, this can safely be done before
294 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
295 if supported by your GnuTLS library. Use the existing
296 "gnutls_require_protocols" option to downgrade this if that will be a
297 problem. Prior to this release, supported values were "TLS1" and "SSL3",
298 so you should be able to update configuration prior to update.
300 [nb: gnutls_require_protocols removed in Exim 4.80, instead use
301 tls_require_ciphers to provide a priority string; see notes above]
303 * The match_<type>{string1}{string2} expansion conditions no longer subject
304 string2 to string expansion, unless Exim was built with the new
305 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
306 insecure configurations that way. If you need the functionality and turn on
307 that build option, please let the developers know, and know why, so we can
308 try to provide a safer mechanism for you.
310 The match{}{} expansion condition (for regular expressions) is NOT affected.
311 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
312 change is that a '$' appearing in s2 will not trigger expansion, but instead
313 will be treated as a literal $ sign; the effect is very similar to having
314 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
315 uses $expansions then those _will_ be processed as normal. It is only the
316 point at which s2 is read where expansion is inhibited.
318 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
319 If you are testing if the address in s1 occurs in the list of items given
320 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
321 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
327 * The integrated support for dynamically loadable lookup modules has an ABI
328 change from the modules supported by some OS vendors through an unofficial
329 patch. Don't try to mix & match.
331 * Some parts of the build system are now beginning to assume that the host
332 environment is POSIX. If you're building on a system where POSIX tools are
333 not the default, you might have an easier time if you switch to the POSIX
334 tools. Feel free to report non-POSIX issues as a request for a feature
335 enhancement, but if the POSIX variants are available then the fix will
336 probably just involve some coercion. See the README instructions for
337 building on such hosts.
343 * The Exim run-time user can no longer be root; this was always
344 strongly discouraged, but is now prohibited both at build and
345 run-time. If you need Exim to run routinely as root, you'll need to
346 patch the source and accept the risk. Here be dragons.
348 * Exim will no longer accept a configuration file owned by the Exim
349 run-time user, unless that account is explicitly the value in
350 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
351 files are not writeable by other accounts.
353 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
354 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
355 Two new build options mitigate this.
357 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
358 files that are trusted to be selected by the Exim user; one per line.
359 This is the recommended approach going forward.
361 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
362 the Exim run-time user may safely pass without dropping privileges.
363 Because changes to this involve a recompile, this is not the recommended
364 approach but may ease transition. The values of the macros, when
365 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
367 * The system_filter_user option now defaults to the Exim run-time user,
368 rather than root. You can still set it explicitly to root and this
369 can be done with prior versions too, letting you roll versions
370 without needing to change this configuration option.
372 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
373 defined at build time.
379 1. Experimental Yahoo! Domainkeys support has been dropped in this release.
380 It has been superseded by a native implementation of its successor DKIM.
382 2. Up to version 4.69, Exim came with an embedded version of the PCRE library.
383 As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
384 installed. Most OS distributions have ready-made library and development
391 1. The internal implementation of the database keys that are used for ACL
392 ratelimiting has been tidied up. This means that an update to 4.68 might cause
393 Exim to "forget" previous rates that it had calculated, and reset them to zero.
399 1. Callouts were setting the name used for EHLO/HELO from $smtp_active_
400 hostname. This is wrong, because it relates to the incoming message (and
401 probably the interface on which it is arriving) and not to the outgoing
402 callout (which could be using a different interface). This has been
403 changed to use the value of the helo_data option from the smtp transport
404 instead - this is what is used when a message is actually being sent. If
405 there is no remote transport (possible with a router that sets up host
406 addresses), $smtp_active_hostname is used. This change is mentioned here in
407 case somebody is relying on the use of $smtp_active_hostname.
409 2. A bug has been fixed that might just possibly be something that is relied on
410 in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
411 empty string (that is {}) was being interpreted as if it was {0} and therefore
412 treated as the number zero. From release 4.64, such strings cause an error
413 because a decimal number, possibly followed by K or M, is required (as has
414 always been documented).
416 3. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
417 Exim's performance. Unfortunately, this has the side effect of being slightly
418 non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
419 one of these earlier versions and you use GnuTLS, you must remove the file
420 called gnutls-params in Exim's spool directory. If you don't do this, you will
423 TLS error on connection from ... (DH params import): Base64 decoding error.
425 Removing the file causes Exim to recompute the relevant encryption parameters
426 and cache them in the new format that was introduced for release 4.51 (May
427 2005). If you are upgrading from release 4.51 or later, there should be no
434 When an SMTP error message is specified in a "message" modifier in an ACL, or
435 in a :fail: or :defer: message in a redirect router, Exim now checks the start
436 of the message for an SMTP error code. This consists of three digits followed
437 by a space, optionally followed by an extended code of the form n.n.n, also
438 followed by a space. If this is the case and the very first digit is the same
439 as the default error code, the code from the message is used instead. If the
440 very first digit is incorrect, a panic error is logged, and the default code is
441 used. This is an incompatible change, but it is not expected to affect many (if
442 any) configurations. It is possible to suppress the use of the supplied code in
443 a redirect router by setting the smtp_error_code option false. In this case,
444 any SMTP code is quietly ignored.
450 1. The default number of ACL variables of each type has been increased to 20,
451 and it's possible to compile Exim with more. You can safely upgrade to this
452 release if you already have messages on the queue with saved ACL variable
453 values. However, if you downgrade from this release with messages on the queue,
454 any saved ACL values they may have will be lost.
456 2. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
462 There was a problem with 4.52/TF/02 in that a "name=" option on control=
463 submission terminated at the next slash, thereby not allowing for slashes in
464 the name. This has been changed so that "name=" takes the rest of the string as
465 its data. It must therefore be the last option.
471 If you are using the experimental Domain Keys support, you must upgrade to
472 at least libdomainkeys 0.67 in order to run this release of Exim.
478 1. The format in which GnuTLS parameters are cached (in the file gnutls-params
479 in the spool directory) has been changed. The new format can also be generated
480 externally, so it is now possible to update the values from outside Exim. This
481 has been implemented in an upwards, BUT NOT downwards, compatible manner.
482 Upgrading should be seamless: when Exim finds that it cannot understand an
483 existing cache file, it generates new parameters and writes them to the cache
484 in the new format. If, however, you downgrade from 4.51 to a previous release,
485 you MUST delete the gnutls-params file in the spool directory, because the
486 older Exim will not recognize the new format.
488 2. When doing a callout as part of verifying an address, Exim was not paying
489 attention to any local part prefix or suffix that was matched by the router
490 that accepted the address. It now behaves in the same way as it does for
491 delivery: the affixes are removed from the local part unless
492 rcpt_include_affixes is set on the transport. If you have a configuration that
493 uses prefixes or suffixes on addresses that could be used for callouts, and you
494 want the affixes to be retained, you must make sure that rcpt_include_affixes
495 is set on the transport.
497 3. Bounce and delay warning messages no longer contain details of delivery
498 errors, except for explicit messages (e.g. generated by :fail:) and SMTP
499 responses from remote hosts.
505 The exicyclog script has been updated to use three-digit numbers in rotated log
506 files if the maximum number to keep is greater than 99. If you are already
507 keeping more than 99, there will be an incompatible change when you upgrade.
508 You will probably want to rename your old log files to the new form before
509 running the new exicyclog.
515 RFC 3848 specifies standard names for the "with" phrase in Received: header
516 lines when AUTH and/or TLS are in use. This is the "received protocol"
517 field. Exim used to use "asmtp" for authenticated SMTP, without any
518 indication (in the protocol name) for TLS use. Now it follows the RFC and
519 uses "esmtpa" if the connection is authenticated, "esmtps" if it is
520 encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
521 appear in log lines as well as in Received: header lines.
527 Change 4.31/2 gave problems to data ACLs and local_scan() functions that
528 expected to see a Received: header. I have changed to yet another scheme. The
529 Received: header is now generated after the body is received, but before the
530 ACL or local_scan() is called. After they have run, the timestamp in the
531 Received: header is updated.
533 Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
534 which is lucky, since I decided it was a bug fix.
540 If an expansion in a condition on a "warn" statement fails because a lookup
541 defers, the "warn" statement is abandoned, and the next ACL statement is
542 processed. Previously this caused the whole ACL to be aborted.
548 Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
549 verification now uses <> in the MAIL command by default, as it did before. A
550 new callout option, "use_sender", has been added to request the other
557 1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
558 or greater. The interface to the obsolete 0.8.x releases is no longer
559 supported. There is one externally visible change: the format for the
560 display of Distinguished Names now uses commas as a separator rather than a
561 slash. This is to comply with RFC 2253.
563 2. When a message is received, the Received: header line is now generated when
564 reception is complete, instead of at the start of reception. For messages
565 that take a long time to come in, this changes the meaning of the timestamp.
566 There are several side-effects of this change:
568 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
569 the logged header lines no longer include the local Received: line,
570 because it has not yet been created. If the message is a non-SMTP one,
571 and the error is processed by sending a message to the sender, the copy
572 of the original message that is returned does not have an added
575 (b) When a filter file is tested using -bf, no additional Received: header
576 is added to the test message. After some thought, I decided that this
579 The contents of $received_for are not affected by this change. This
580 variable still contains the single recipient of a message, copied after
581 addresses have been rewritten, but before local_scan() is run.
583 2. Recipient callout verification, like sender verification, was using <> in
584 the MAIL FROM command. This isn't really the right thing, since the actual
585 sender may affect whether the remote host accepts the recipient or not. I
586 have changed it to use the actual sender in the callout; this means that
587 the cache record is now keyed on a recipient/sender pair, not just the
588 recipient address. There doesn't seem to be a real danger of callout loops,
589 since a callout by the remote host to check the sender would use <>.
595 1. I have abolished timeout_DNS as an error that can be detected in retry
596 rules, because it has never worked. Despite the fact that it has been
597 documented since at least release 1.62, there was no code to support it.
598 If you have used it in your retry rules, you will now get a warning message
599 to the log and panic log. It is now treated as plain "timeout".
601 2. After discussion on the mailing list, Exim no longer adds From:, Date:, or
602 Message-Id: header lines to messages that do not originate locally, that is,
603 messages that have an associated sending host address.
605 3. When looking up a host name from an IP address, Exim now tries the DNS
606 first, and only if that fails does it use gethostbyaddr() (or equivalent).
607 This change was made because on some OS, not all the names are given for
608 addresses with multiple PTR records via the gethostbyaddr() interface. The
609 order of lookup can be changed by setting host_lookup_order.
615 1. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
616 that cannot be overridden. The default in the distributed EDITME is "root".
617 If for some reason you were (against advice) running deliveries as root, you
618 will have to ensure that FIXED_NEVER_USERS is not set in your
621 2. The ${quote: operator now quotes an empty string, which it did not before.
623 3. Version 4.23 saves the contents of the ACL variables with the message, so
624 that they can be used later. If one of these variables contains a newline,
625 there will be a newline character in the spool that will not be interpreted
626 correctly by a previous version of Exim. (Exim ignores keyed spool file
627 items that it doesn't understand - precisely for this kind of problem - but
628 it expects them all to be on one line.)
630 So the bottom line is: if you have newlines in your ACL variables, you
631 cannot retreat from 4.23.
637 1. The idea of the "warn" ACL verb is that it adds a header or writes to the
638 log only when "message" or "log_message" are set. However, if one of the
639 conditions was an address verification, or a call to a nested ACL, the
640 messages generated by the underlying test were being passed through. This
641 no longer happens. The underlying message is available in $acl_verify_
642 message for both "message" and "log_message" expansions, so it can be
643 passed through if needed.
645 2. The way that the $h_ (and $header_) expansions work has been changed by the
646 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
647 until release 4.30, then the manual) for full details. Briefly, there are
650 $rh_xxx: and $rheader_xxx: give the original content of the header
651 line(s), with no processing at all.
653 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
654 then decode base64 or quoted-printable "words" within the header text,
655 but do not do charset translation.
657 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
658 standard character set.
660 If you have previously been using $h_ expansions to access the raw
661 characters, you should change to $rh_ instead.
663 3. When Exim creates an RFC 2047 encoded word in a header line, it labels it
664 with the default character set from the headers_charset option instead of
665 always using iso-8859-1.
667 4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
668 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
669 called TMPDIR, and if it finds it is different, it changes its value.
671 5. Following a discussion on the list, the rules by which Exim recognises line
672 endings on incoming messages have been changed. The -dropcr and drop_cr
673 options are now no-ops, retained only for backwards compatibility. The
674 following line terminators are recognized: LF CRLF CR. However, special
675 processing applies to CR:
677 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
678 nor a local message in the state where . is a terminator.
680 (ii) If a bare CR is encountered in a header line, an extra space is added
681 after the line terminator so as not to end the header. The reasoning
682 behind this is that bare CRs in header lines are most likely either
683 to be mistakes, or people trying to play silly games.
685 6. The code for using daemon_smtp_port, local_interfaces, and the -oX options
686 has been reorganized. It is supposed to be backwards compatible, but it is
687 mentioned here just in case I've screwed up.
694 1. I have tidied and re-organized the code that uses alarm() for imposing time
695 limits on various things. It shouldn't affect anything, but if you notice
696 processes getting stuck, it may be that I've broken something.
698 2. The "arguments" log selector now also logs the current working directory
701 3. An incompatible change has been made to the appendfile transport. This
702 affects the case when it is used for file deliveries that are set up by
703 .forward and filter files. Previously, any settings of the "file" or
704 "directory" options were ignored. It is hoped that, like the address_file
705 transport in the default configuration, these options were never in fact set
706 on such transports, because they were of no use.
708 Now, if either of these options is set, it is used. The path that is passed
709 by the router is in $address_file (this is not new), so it can be used as
710 part of a longer path, or modified in any other way that expansion permits.
712 If neither "file" nor "directory" is set, the behaviour is unchanged.
714 4. Related to the above: in a filter, if a "save" command specifies a non-
715 absolute path, the value of $home/ is pre-pended. This no longer happens if
716 $home is unset or is set to an empty string.
718 5. Multiple file deliveries from a filter or .forward file can never be
719 batched; the value of batch_max on the transport is ignored for file
720 deliveries. I'm assuming that nobody ever actually set batch_max on the
721 address_file transport - it would have had odd effects previously.
723 6. DESTDIR is the more common variable that ROOT for use when installing
724 software under a different root filing system. The Exim install script now
725 recognizes DESTDIR first; if it is not set, ROOT is used.
727 7. If DESTDIR is set when installing Exim, it no longer prepends its value to
728 the path of the system aliases file that appears in the default
729 configuration (when a default configuration is installed). If an aliases
730 file is actually created, its name *does* use the prefix.
736 1. The default for the maximum number of unknown SMTP commands that Exim will
737 accept before dropping a connection has been reduced from 5 to 3. However, you
738 can now change the value by setting smtp_max_unknown_commands.
740 2. The ${quote: operator has been changed so that it turns newline and carriage
741 return characters into \n and \r, respectively.
743 3. The file names used for maildir messages now include the microsecond time
744 fraction as well as the time in seconds, to cope with systems where the process
745 id can be re-used within the same second. The format is now
747 <time>.H<microsec>P<pid>.<host>
749 This should be a compatible change, but is noted here just in case.
751 4. The rules for creating message ids have changed, to cope with systems where
752 the process id can be re-used within the same second. The format, however, is
753 unchanged, so this should not cause any problems, except as noted in the next
756 5. The maximum value for localhost_number has been reduced from 255 to 16, in
757 order to implement the new message id rules. For operating systems that have
758 case-insensitive file systems (Cygwin and Darwin), the limit is 10.
760 6. verify = header_syntax was allowing unqualified addresses in all cases. Now
761 it allows them only for locally generated messages and from hosts that match
762 sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
764 7. For reasons lost in the mists of time, when a pipe transport was run, the
765 environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
766 form used in Message-ID: header lines). The 'E' has been removed.
772 1. The handling of lines in the configuration file has changed. Previously,
773 macro expansion was applied to logical lines, after continuations had been
774 joined on. This meant that it could not be used in .include lines, which are
775 handled as physical rather than logical lines. Macro expansion is now done on
776 physical lines rather than logical lines. This means there are two
779 (a) A macro that expands to # to turn a line into a comment now applies only
780 to the physical line where it appears. Previously, it would have caused
781 any following continuations also to be ignored.
783 (b) A macro name can no longer be split over the boundary between a line and
784 its continuation. Actually, this is more of a bug fix. :-)
786 2. The -D command line option must now all be within one command line item.
787 This makes it possible to use -D to set a macro to the empty string by commands
793 Previously, these items would have moved on to the next item on the command
794 line. To include spaces in a macro definition item, quotes must be used, in
795 which case you can also have spaces after -D and surrounding the equals. For
798 exim '-D ABC = something' ...
800 3. The way that addresses that redirect to themselves are handled has been
801 changed, in order to fix an obscure bug. This should not cause any problems
802 except in the case of wanting to go back from a 4.11 (or later) release to an
803 earlier release. If there are undelivered messages on the spool that contain
804 addresses which redirect to themselves, and the redirected addresses have
805 already been delivered, you might get a duplicate delivery if you revert to an
808 4. The default way of looking up IP addresses for hosts in the manualroute and
809 queryprogram routers has been changed. If "byname" or "bydns" is explicitly
810 specified, there is no change, but if no method is specified, Exim now behaves
813 First, a DNS lookup is done. If this yields anything other than
814 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
815 getipnodebyname() (or gethostbyname() on older systems) and the result of the
816 lookup is the result of that call.
818 This change has been made because it has been discovered that on some systems,
819 if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
820 returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
821 first, and only if that gives a definite "no such host" to try the local
824 5. In fixing the minor security problem with pid_file_path, I have removed some
825 backwards-compatible (undocumented) code which was present to ease conversion
826 from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
827 contain "%s", which was replaced by the port number for daemons listening on
828 non-standard ports. In Exim 4, such daemons do not write a pid file. The
829 backwards compatibility feature was to replace "%s" by nothing if it occurred
830 in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
831 the problem by removing the backwards compatibility feature. Thus, if you still
832 have "%s" somewhere in a setting of pid_file_path, you should remove it.
834 6. There has been an extension to lsearch files. The keys in these files may
835 now be quoted in order to allow for whitespace and colons in them. This means
836 that if you were previously using keys that began with a doublequote, you will
837 now have to wrap them with extra quotes and escape the internal quotes. The
838 possibility that anybody is actually doing this seems extremely remote, but it
839 is documented just in case.
845 The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
846 to better reflect its function. The OS-specific files have been updated. Only
847 if you have explicitly set this in your Makefile (highly unlikely) do you need
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