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.
32 * New option gnutls_enable_pkcs11 defaults false; if you have GnuTLS 2.12.0
33 or later and do want PKCS11 modules to be autoloaded, then set this option.
35 * A per-transport wait-<name> database is no longer updated if the transport
36 sets "connection_max_messages" to 1, as it can not be used and causes
37 unnecessary serialisation and load. External tools tracking the state of
38 Exim by the hints databases may need modification to take this into account.
40 * The av_scanner option can now accept multiple clamd TCP targets, all other
41 setting limitations remain.
47 * BEWARE backwards-incompatible changes in SSL libraries, thus the version
48 bump. See points below for details.
49 Also an LDAP data returned format change.
51 * The value of $tls_peerdn is now print-escaped when written to the spool file
52 in a -tls_peerdn line, and unescaped when read back in. We received reports
53 of values with embedded newlines, which caused spool file corruption.
55 If you have a corrupt spool file and you wish to recover the contents after
56 upgrading, then lock the message, replace the new-lines that should be part
57 of the -tls_peerdn line with the two-character sequence \n and then unlock
58 the message. No tool has been provided as we believe this is a rare
61 * For OpenSSL, SSLv2 is now disabled by default. (GnuTLS does not support
62 SSLv2). RFC 6176 prohibits SSLv2 and some informal surveys suggest no
63 actual usage. You can re-enable with the "openssl_options" Exim option,
64 in the main configuration section. Note that supporting SSLv2 exposes
65 you to ciphersuite downgrade attacks.
67 * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built
68 against 1.0.1a then you will get a warning message and the
69 "openssl_options" value will not parse "no_tlsv1_1": the value changes
70 incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a
71 is infelicitous. We advise avoiding 1.0.1a.
73 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
75 COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
76 "+dont_insert_empty_fragments". We default to "+no_sslv2".
77 That old default was grandfathered in from before openssl_options became a
79 Empty fragments are inserted by default through TLS1.0, to partially defend
80 against certain attacks; TLS1.1+ change the protocol so that this is not
81 needed. The DIEF SSL option was required for some old releases of mail
82 clients which did not gracefully handle the empty fragments, and was
83 initially set in Exim release 4.31 (see ChangeLog, item 37).
85 If you still have affected mail-clients, and you see SSL protocol failures
86 with this release of Exim, set:
87 openssl_options = +dont_insert_empty_fragments
88 in the main section of your Exim configuration file. You're trading off
89 security for compatibility. Exim is now defaulting to higher security and
90 rewarding more modern clients.
92 If the option tls_dhparams is set and the parameters loaded from the file
93 have a bit-count greater than the new option tls_dh_max_bits, then the file
94 will now be ignored. If this affects you, raise the tls_dh_max_bits limit.
95 We suspect that most folks are using dated defaults and will not be affected.
97 * Ldap lookups returning multi-valued attributes now separate the attributes
98 with only a comma, not a comma-space sequence. Also, an actual comma within
99 a returned attribute is doubled. This makes it possible to parse the
100 attribute as a comma-separated list. Note the distinction from multiple
101 attributes being returned, where each one is a name=value pair.
103 If you are currently splitting the results from LDAP upon a comma, then you
104 should check carefully to see if adjustments are needed.
106 This change lets cautious folks distinguish "comma used as separator for
107 joining values" from "comma inside the data".
109 * accept_8bitmime now defaults on, which is not RFC compliant but is better
110 suited to today's Internet. See http://cr.yp.to/smtp/8bitmime.html for a
111 sane rationale. Those who wish to be strictly RFC compliant, or know that
112 they need to talk to servers that are not 8-bit-clean, now need to take
113 explicit configuration action to default this option off. This is not a
114 new option, you can safely force it off before upgrading, to decouple
115 configuration changes from the binary upgrade while remaining RFC compliant.
117 * The GnuTLS support has been mostly rewritten, to use APIs which don't cause
118 deprecation warnings in GnuTLS 2.12.x. As part of this, these three options
119 are no longer supported:
123 gnutls_require_protocols
125 Their functionality is entirely subsumed into tls_require_ciphers. In turn,
126 tls_require_ciphers is no longer an Exim list and is not parsed by Exim, but
127 is instead given to gnutls_priority_init(3), which expects a priority string;
128 this behaviour is much closer to the OpenSSL behaviour. See:
130 http://www.gnutls.org/manual/html_node/Priority-Strings.html
132 for fuller documentation of the strings parsed. The three gnutls_require_*
133 options are still parsed by Exim and, for this release, silently ignored.
134 A future release will add warnings, before a later still release removes
135 parsing entirely and the presence of the options will be a configuration
138 Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains.
139 A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may
140 re-enable support, but this is not supported by the Exim maintainers.
141 Our test suite no longer includes MD5-based certificates.
143 This rewrite means that Exim will continue to build against GnuTLS in the
144 future, brings Exim closer to other GnuTLS applications and lets us add
145 support for SNI and other features more readily. We regret that it wasn't
146 feasible to retain the three dropped options.
148 * If built with TLS support, then Exim will now validate the value of
149 the main section tls_require_ciphers option at start-up. Before, this
150 would cause a STARTTLS 4xx failure, now it causes a failure to start.
151 Running with a broken configuration which causes failures that may only
152 be left in the logs has been traded off for something more visible. This
153 change makes an existing problem more prominent, but we do not believe
154 anyone would deliberately be running with an invalid tls_require_ciphers
157 This also means that library linkage issues caused by conflicts of some
158 kind might take out the main daemon, not just the delivery or receiving
159 process. Conceivably some folks might prefer to continue delivering
160 mail plaintext when their binary is broken in this way, if there is a
161 server that is a candidate to receive such mails that does not advertise
162 STARTTLS. Note that Exim is typically a setuid root binary and given
163 broken linkage problems that cause segfaults, we feel it is safer to
164 fail completely. (The check is not done as root, to ensure that problems
165 here are not made worse by the check).
167 * The "tls_dhparam" option has been updated, so that it can now specify a
168 path or an identifier for a standard DH prime from one of a few RFCs.
169 The default for OpenSSL is no longer to not use DH but instead to use
170 one of these standard primes. The default for GnuTLS is no longer to use
171 a file in the spool directory, but to use that same standard prime.
172 The option is now used by GnuTLS too. If it points to a path, then
173 GnuTLS will use that path, instead of a file in the spool directory;
174 GnuTLS will attempt to create it if it does not exist.
176 To preserve the previous behaviour of generating files in the spool
177 directory, set "tls_dhparam = historic". Since prior releases of Exim
178 ignored tls_dhparam when using GnuTLS, this can safely be done before
186 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
187 if supported by your GnuTLS library. Use the existing
188 "gnutls_require_protocols" option to downgrade this if that will be a
189 problem. Prior to this release, supported values were "TLS1" and "SSL3",
190 so you should be able to update configuration prior to update.
192 [nb: gnutls_require_protocols removed in Exim 4.80, instead use
193 tls_require_ciphers to provide a priority string; see notes above]
195 * The match_<type>{string1}{string2} expansion conditions no longer subject
196 string2 to string expansion, unless Exim was built with the new
197 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
198 insecure configurations that way. If you need the functionality and turn on
199 that build option, please let the developers know, and know why, so we can
200 try to provide a safer mechanism for you.
202 The match{}{} expansion condition (for regular expressions) is NOT affected.
203 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
204 change is that a '$' appearing in s2 will not trigger expansion, but instead
205 will be treated as a literal $ sign; the effect is very similar to having
206 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
207 uses $expansions then those _will_ be processed as normal. It is only the
208 point at which s2 is read where expansion is inhibited.
210 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
211 If you are testing if the address in s1 occurs in the list of items given
212 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
213 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
219 * The integrated support for dynamically loadable lookup modules has an ABI
220 change from the modules supported by some OS vendors through an unofficial
221 patch. Don't try to mix & match.
223 * Some parts of the build system are now beginning to assume that the host
224 environment is POSIX. If you're building on a system where POSIX tools are
225 not the default, you might have an easier time if you switch to the POSIX
226 tools. Feel free to report non-POSIX issues as a request for a feature
227 enhancement, but if the POSIX variants are available then the fix will
228 probably just involve some coercion. See the README instructions for
229 building on such hosts.
235 * The Exim run-time user can no longer be root; this was always
236 strongly discouraged, but is now prohibited both at build and
237 run-time. If you need Exim to run routinely as root, you'll need to
238 patch the source and accept the risk. Here be dragons.
240 * Exim will no longer accept a configuration file owned by the Exim
241 run-time user, unless that account is explicitly the value in
242 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
243 files are not writeable by other accounts.
245 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
246 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
247 Two new build options mitigate this.
249 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
250 files that are trusted to be selected by the Exim user; one per line.
251 This is the recommended approach going forward.
253 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
254 the Exim run-time user may safely pass without dropping privileges.
255 Because changes to this involve a recompile, this is not the recommended
256 approach but may ease transition. The values of the macros, when
257 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
259 * The system_filter_user option now defaults to the Exim run-time user,
260 rather than root. You can still set it explicitly to root and this
261 can be done with prior versions too, letting you roll versions
262 without needing to change this configuration option.
264 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
265 defined at build time.
271 1. Experimental Yahoo! Domainkeys support has been dropped in this release.
272 It has been superceded by a native implementation of its successor DKIM.
274 2. Up to version 4.69, Exim came with an embedded version of the PCRE library.
275 As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
276 installed. Most OS distributions have ready-made library and development
283 1. The internal implementation of the database keys that are used for ACL
284 ratelimiting has been tidied up. This means that an update to 4.68 might cause
285 Exim to "forget" previous rates that it had calculated, and reset them to zero.
291 1. Callouts were setting the name used for EHLO/HELO from $smtp_active_
292 hostname. This is wrong, because it relates to the incoming message (and
293 probably the interface on which it is arriving) and not to the outgoing
294 callout (which could be using a different interface). This has been
295 changed to use the value of the helo_data option from the smtp transport
296 instead - this is what is used when a message is actually being sent. If
297 there is no remote transport (possible with a router that sets up host
298 addresses), $smtp_active_hostname is used. This change is mentioned here in
299 case somebody is relying on the use of $smtp_active_hostname.
301 2. A bug has been fixed that might just possibly be something that is relied on
302 in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
303 empty string (that is {}) was being interpreted as if it was {0} and therefore
304 treated as the number zero. From release 4.64, such strings cause an error
305 because a decimal number, possibly followed by K or M, is required (as has
306 always been documented).
308 3. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
309 Exim's performance. Unfortunately, this has the side effect of being slightly
310 non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
311 one of these earlier versions and you use GnuTLS, you must remove the file
312 called gnutls-params in Exim's spool directory. If you don't do this, you will
315 TLS error on connection from ... (DH params import): Base64 decoding error.
317 Removing the file causes Exim to recompute the relevant encryption parameters
318 and cache them in the new format that was introduced for release 4.51 (May
319 2005). If you are upgrading from release 4.51 or later, there should be no
326 When an SMTP error message is specified in a "message" modifier in an ACL, or
327 in a :fail: or :defer: message in a redirect router, Exim now checks the start
328 of the message for an SMTP error code. This consists of three digits followed
329 by a space, optionally followed by an extended code of the form n.n.n, also
330 followed by a space. If this is the case and the very first digit is the same
331 as the default error code, the code from the message is used instead. If the
332 very first digit is incorrect, a panic error is logged, and the default code is
333 used. This is an incompatible change, but it is not expected to affect many (if
334 any) configurations. It is possible to suppress the use of the supplied code in
335 a redirect router by setting the smtp_error_code option false. In this case,
336 any SMTP code is quietly ignored.
342 1. The default number of ACL variables of each type has been increased to 20,
343 and it's possible to compile Exim with more. You can safely upgrade to this
344 release if you already have messages on the queue with saved ACL variable
345 values. However, if you downgrade from this release with messages on the queue,
346 any saved ACL values they may have will be lost.
348 2. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
354 There was a problem with 4.52/TF/02 in that a "name=" option on control=
355 submission terminated at the next slash, thereby not allowing for slashes in
356 the name. This has been changed so that "name=" takes the rest of the string as
357 its data. It must therefore be the last option.
363 If you are using the experimental Domain Keys support, you must upgrade to
364 at least libdomainkeys 0.67 in order to run this release of Exim.
370 1. The format in which GnuTLS parameters are cached (in the file gnutls-params
371 in the spool directory) has been changed. The new format can also be generated
372 externally, so it is now possible to update the values from outside Exim. This
373 has been implemented in an upwards, BUT NOT downwards, compatible manner.
374 Upgrading should be seamless: when Exim finds that it cannot understand an
375 existing cache file, it generates new parameters and writes them to the cache
376 in the new format. If, however, you downgrade from 4.51 to a previous release,
377 you MUST delete the gnutls-params file in the spool directory, because the
378 older Exim will not recognize the new format.
380 2. When doing a callout as part of verifying an address, Exim was not paying
381 attention to any local part prefix or suffix that was matched by the router
382 that accepted the address. It now behaves in the same way as it does for
383 delivery: the affixes are removed from the local part unless
384 rcpt_include_affixes is set on the transport. If you have a configuration that
385 uses prefixes or suffixes on addresses that could be used for callouts, and you
386 want the affixes to be retained, you must make sure that rcpt_include_affixes
387 is set on the transport.
389 3. Bounce and delay warning messages no longer contain details of delivery
390 errors, except for explicit messages (e.g. generated by :fail:) and SMTP
391 responses from remote hosts.
397 The exicyclog script has been updated to use three-digit numbers in rotated log
398 files if the maximum number to keep is greater than 99. If you are already
399 keeping more than 99, there will be an incompatible change when you upgrade.
400 You will probably want to rename your old log files to the new form before
401 running the new exicyclog.
407 RFC 3848 specifies standard names for the "with" phrase in Received: header
408 lines when AUTH and/or TLS are in use. This is the "received protocol"
409 field. Exim used to use "asmtp" for authenticated SMTP, without any
410 indication (in the protocol name) for TLS use. Now it follows the RFC and
411 uses "esmtpa" if the connection is authenticated, "esmtps" if it is
412 encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
413 appear in log lines as well as in Received: header lines.
419 Change 4.31/2 gave problems to data ACLs and local_scan() functions that
420 expected to see a Received: header. I have changed to yet another scheme. The
421 Received: header is now generated after the body is received, but before the
422 ACL or local_scan() is called. After they have run, the timestamp in the
423 Received: header is updated.
425 Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
426 which is lucky, since I decided it was a bug fix.
432 If an expansion in a condition on a "warn" statement fails because a lookup
433 defers, the "warn" statement is abandoned, and the next ACL statement is
434 processed. Previously this caused the whole ACL to be aborted.
440 Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
441 verification now uses <> in the MAIL command by default, as it did before. A
442 new callout option, "use_sender", has been added to request the other
449 1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
450 or greater. The interface to the obsolete 0.8.x releases is no longer
451 supported. There is one externally visible change: the format for the
452 display of Distinguished Names now uses commas as a separator rather than a
453 slash. This is to comply with RFC 2253.
455 2. When a message is received, the Received: header line is now generated when
456 reception is complete, instead of at the start of reception. For messages
457 that take a long time to come in, this changes the meaning of the timestamp.
458 There are several side-effects of this change:
460 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
461 the logged header lines no longer include the local Received: line,
462 because it has not yet been created. If the message is a non-SMTP one,
463 and the error is processed by sending a message to the sender, the copy
464 of the original message that is returned does not have an added
467 (b) When a filter file is tested using -bf, no additional Received: header
468 is added to the test message. After some thought, I decided that this
471 The contents of $received_for are not affected by this change. This
472 variable still contains the single recipient of a message, copied after
473 addresses have been rewritten, but before local_scan() is run.
475 2. Recipient callout verification, like sender verification, was using <> in
476 the MAIL FROM command. This isn't really the right thing, since the actual
477 sender may affect whether the remote host accepts the recipient or not. I
478 have changed it to use the actual sender in the callout; this means that
479 the cache record is now keyed on a recipient/sender pair, not just the
480 recipient address. There doesn't seem to be a real danger of callout loops,
481 since a callout by the remote host to check the sender would use <>.
487 1. I have abolished timeout_DNS as an error that can be detected in retry
488 rules, because it has never worked. Despite the fact that it has been
489 documented since at least release 1.62, there was no code to support it.
490 If you have used it in your retry rules, you will now get a warning message
491 to the log and panic log. It is now treated as plain "timeout".
493 2. After discussion on the mailing list, Exim no longer adds From:, Date:, or
494 Message-Id: header lines to messages that do not originate locally, that is,
495 messages that have an associated sending host address.
497 3. When looking up a host name from an IP address, Exim now tries the DNS
498 first, and only if that fails does it use gethostbyaddr() (or equivalent).
499 This change was made because on some OS, not all the names are given for
500 addresses with multiple PTR records via the gethostbyaddr() interface. The
501 order of lookup can be changed by setting host_lookup_order.
507 1. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
508 that cannot be overridden. The default in the distributed EDITME is "root".
509 If for some reason you were (against advice) running deliveries as root, you
510 will have to ensure that FIXED_NEVER_USERS is not set in your
513 2. The ${quote: operator now quotes an empty string, which it did not before.
515 3. Version 4.23 saves the contents of the ACL variables with the message, so
516 that they can be used later. If one of these variables contains a newline,
517 there will be a newline character in the spool that will not be interpreted
518 correctely by a previous version of Exim. (Exim ignores keyed spool file
519 items that it doesn't understand - precisely for this kind of problem - but
520 it expects them all to be on one line.)
522 So the bottom line is: if you have newlines in your ACL variables, you
523 cannot retreat from 4.23.
529 1. The idea of the "warn" ACL verb is that it adds a header or writes to the
530 log only when "message" or "log_message" are set. However, if one of the
531 conditions was an address verification, or a call to a nested ACL, the
532 messages generated by the underlying test were being passed through. This
533 no longer happens. The underlying message is available in $acl_verify_
534 message for both "message" and "log_message" expansions, so it can be
535 passed through if needed.
537 2. The way that the $h_ (and $header_) expansions work has been changed by the
538 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
539 until release 4.30, then the manual) for full details. Briefly, there are
542 $rh_xxx: and $rheader_xxx: give the original content of the header
543 line(s), with no processing at all.
545 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
546 then decode base64 or quoted-printable "words" within the header text,
547 but do not do charset translation.
549 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
550 standard character set.
552 If you have previously been using $h_ expansions to access the raw
553 characters, you should change to $rh_ instead.
555 3. When Exim creates an RFC 2047 encoded word in a header line, it labels it
556 with the default character set from the headers_charset option instead of
557 always using iso-8859-1.
559 4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
560 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
561 called TMPDIR, and if it finds it is different, it changes its value.
563 5. Following a discussion on the list, the rules by which Exim recognises line
564 endings on incoming messages have been changed. The -dropcr and drop_cr
565 options are now no-ops, retained only for backwards compatibility. The
566 following line terminators are recognized: LF CRLF CR. However, special
567 processing applies to CR:
569 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
570 nor a local message in the state where . is a terminator.
572 (ii) If a bare CR is encountered in a header line, an extra space is added
573 after the line terminator so as not to end the header. The reasoning
574 behind this is that bare CRs in header lines are most likely either
575 to be mistakes, or people trying to play silly games.
577 6. The code for using daemon_smtp_port, local_interfaces, and the -oX options
578 has been reorganized. It is supposed to be backwards compatible, but it is
579 mentioned here just in case I've screwed up.
586 1. I have tidied and re-organized the code that uses alarm() for imposing time
587 limits on various things. It shouldn't affect anything, but if you notice
588 processes getting stuck, it may be that I've broken something.
590 2. The "arguments" log selector now also logs the current working directory
593 3. An incompatible change has been made to the appendfile transport. This
594 affects the case when it is used for file deliveries that are set up by
595 .forward and filter files. Previously, any settings of the "file" or
596 "directory" options were ignored. It is hoped that, like the address_file
597 transport in the default configuration, these options were never in fact set
598 on such transports, because they were of no use.
600 Now, if either of these options is set, it is used. The path that is passed
601 by the router is in $address_file (this is not new), so it can be used as
602 part of a longer path, or modified in any other way that expansion permits.
604 If neither "file" nor "directory" is set, the behaviour is unchanged.
606 4. Related to the above: in a filter, if a "save" command specifies a non-
607 absolute path, the value of $home/ is pre-pended. This no longer happens if
608 $home is unset or is set to an empty string.
610 5. Multiple file deliveries from a filter or .forward file can never be
611 batched; the value of batch_max on the transport is ignored for file
612 deliveries. I'm assuming that nobody ever actually set batch_max on the
613 address_file transport - it would have had odd effects previously.
615 6. DESTDIR is the more common variable that ROOT for use when installing
616 software under a different root filing system. The Exim install script now
617 recognizes DESTDIR first; if it is not set, ROOT is used.
619 7. If DESTDIR is set when installing Exim, it no longer prepends its value to
620 the path of the system aliases file that appears in the default
621 configuration (when a default configuration is installed). If an aliases
622 file is actually created, its name *does* use the prefix.
628 1. The default for the maximum number of unknown SMTP commands that Exim will
629 accept before dropping a connection has been reduced from 5 to 3. However, you
630 can now change the value by setting smtp_max_unknown_commands.
632 2. The ${quote: operator has been changed so that it turns newline and carriage
633 return characters into \n and \r, respectively.
635 3. The file names used for maildir messages now include the microsecond time
636 fraction as well as the time in seconds, to cope with systems where the process
637 id can be re-used within the same second. The format is now
639 <time>.H<microsec>P<pid>.<host>
641 This should be a compatible change, but is noted here just in case.
643 4. The rules for creating message ids have changed, to cope with systems where
644 the process id can be re-used within the same second. The format, however, is
645 unchanged, so this should not cause any problems, except as noted in the next
648 5. The maximum value for localhost_number has been reduced from 255 to 16, in
649 order to implement the new message id rules. For operating systems that have
650 case-insensitive file systems (Cygwin and Darwin), the limit is 10.
652 6. verify = header_syntax was allowing unqualified addresses in all cases. Now
653 it allows them only for locally generated messages and from hosts that match
654 sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
656 7. For reasons lost in the mists of time, when a pipe transport was run, the
657 environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
658 form used in Message-ID: header lines). The 'E' has been removed.
664 1. The handling of lines in the configuration file has changed. Previously,
665 macro expansion was applied to logical lines, after continuations had been
666 joined on. This meant that it could not be used in .include lines, which are
667 handled as physical rather than logical lines. Macro expansion is now done on
668 physical lines rather than logical lines. This means there are two
671 (a) A macro that expands to # to turn a line into a comment now applies only
672 to the physical line where it appears. Previously, it would have caused
673 any following continuations also to be ignored.
675 (b) A macro name can no longer be split over the boundary between a line and
676 its continuation. Actually, this is more of a bug fix. :-)
678 2. The -D command line option must now all be within one command line item.
679 This makes it possible to use -D to set a macro to the empty string by commands
685 Previously, these items would have moved on to the next item on the command
686 line. To include spaces in a macro definition item, quotes must be used, in
687 which case you can also have spaces after -D and surrounding the equals. For
690 exim '-D ABC = something' ...
692 3. The way that addresses that redirect to themselves are handled has been
693 changed, in order to fix an obscure bug. This should not cause any problems
694 except in the case of wanting to go back from a 4.11 (or later) release to an
695 earlier release. If there are undelivered messages on the spool that contain
696 addresses which redirect to themselves, and the redirected addresses have
697 already been delivered, you might get a duplicate delivery if you revert to an
700 4. The default way of looking up IP addresses for hosts in the manualroute and
701 queryprogram routers has been changed. If "byname" or "bydns" is explicitly
702 specified, there is no change, but if no method is specified, Exim now behaves
705 First, a DNS lookup is done. If this yields anything other than
706 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
707 getipnodebyname() (or gethostbyname() on older systems) and the result of the
708 lookup is the result of that call.
710 This change has been made because it has been discovered that on some systems,
711 if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
712 returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
713 first, and only if that gives a definite "no such host" to try the local
716 5. In fixing the minor security problem with pid_file_path, I have removed some
717 backwards-compatible (undocumented) code which was present to ease conversion
718 from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
719 contain "%s", which was replaced by the port number for daemons listening on
720 non-standard ports. In Exim 4, such daemons do not write a pid file. The
721 backwards compatibility feature was to replace "%s" by nothing if it occurred
722 in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
723 the problem by removing the backwards compatibility feature. Thus, if you still
724 have "%s" somewhere in a setting of pid_file_path, you should remove it.
726 6. There has been an extension to lsearch files. The keys in these files may
727 now be quoted in order to allow for whitespace and colons in them. This means
728 that if you were previously using keys that began with a doublequote, you will
729 now have to wrap them with extra quotes and escape the internal quotes. The
730 possibility that anybody is actually doing this seems extremely remote, but it
731 is documented just in case.
737 The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
738 to better reflect its function. The OS-specific files have been updated. Only
739 if you have explicitly set this in your Makefile (highly unlikely) do you need
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