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 * The value of $tls_peerdn is now print-escaped when written to the spool file
33 in a -tls_peerdn line, and unescaped when read back in. We received reports
34 of values with embedded newlines, which caused spool file corruption.
36 If you have a corrupt spool file and you wish to recover the contents after
37 upgrading, then lock the message, replace the new-lines that should be part
38 of the -tls_peerdn line with the two-character sequence \n and then unlock
39 the message. No tool has been provided as we believe this is a rare
42 * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built
43 against 1.0.1a then you will get a warning message and the
44 "openssl_options" value will not parse "no_tlsv1_1": the value changes
45 incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a
46 is infelicitous. We advise avoiding 1.0.1a.
48 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
50 COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
51 "+dont_insert_empty_fragments". We default to unset. That old default was
52 grandfathered in from before openssl_options became a configuration option.
53 Empty fragments are inserted by default through TLS1.0, to partially defend
54 against certain attacks; TLS1.1+ change the protocol so that this is not
55 needed. The DIEF SSL option was required for some old releases of mail
56 clients which did not gracefully handle the empty fragments, and was
57 initially set in Exim release 4.31 (see ChangeLog, item 37).
59 If you still have affected mail-clients, and you see SSL protocol failures
60 with this release of Exim, set:
61 openssl_options = +dont_insert_empty_fragments
62 in the main section of your Exim configuration file. You're trading off
63 security for compatibility. Exim is now defaulting to higher security and
64 rewarding more modern clients.
66 * Ldap lookups returning multi-valued attributes now separate the attributes
67 with only a comma, not a comma-space sequence. Also, an actual comma within
68 a returned attribute is doubled. This makes it possible to parse the
69 attribute as a comma-separated list. Note the distinction from multiple
70 attributes being returned, where each one is a name=value pair.
76 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
77 if supported by your GnuTLS library. Use the existing
78 "gnutls_require_protocols" option to downgrade this if that will be a
79 problem. Prior to this release, supported values were "TLS1" and "SSL3",
80 so you should be able to update configuration prior to update.
82 * The match_<type>{string1}{string2} expansion conditions no longer subject
83 string2 to string expansion, unless Exim was built with the new
84 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
85 insecure configurations that way. If you need the functionality and turn on
86 that build option, please let the developers know, and know why, so we can
87 try to provide a safer mechanism for you.
89 The match{}{} expansion condition (for regular expressions) is NOT affected.
90 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
91 change is that a '$' appearing in s2 will not trigger expansion, but instead
92 will be treated as a literal $ sign; the effect is very similar to having
93 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
94 uses $expansions then those _will_ be processed as normal. It is only the
95 point at which s2 is read where expansion is inhibited.
97 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
98 If you are testing if the address in s1 occurs in the list of items given
99 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
100 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
106 * The integrated support for dynamically loadable lookup modules has an ABI
107 change from the modules supported by some OS vendors through an unofficial
108 patch. Don't try to mix & match.
110 * Some parts of the build system are now beginning to assume that the host
111 environment is POSIX. If you're building on a system where POSIX tools are
112 not the default, you might have an easier time if you switch to the POSIX
113 tools. Feel free to report non-POSIX issues as a request for a feature
114 enhancement, but if the POSIX variants are available then the fix will
115 probably just involve some coercion. See the README instructions for
116 building on such hosts.
122 * The Exim run-time user can no longer be root; this was always
123 strongly discouraged, but is now prohibited both at build and
124 run-time. If you need Exim to run routinely as root, you'll need to
125 patch the source and accept the risk. Here be dragons.
127 * Exim will no longer accept a configuration file owned by the Exim
128 run-time user, unless that account is explicitly the value in
129 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
130 files are not writeable by other accounts.
132 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
133 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
134 Two new build options mitigate this.
136 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
137 files that are trusted to be selected by the Exim user; one per line.
138 This is the recommended approach going forward.
140 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
141 the Exim run-time user may safely pass without dropping privileges.
142 Because changes to this involve a recompile, this is not the recommended
143 approach but may ease transition. The values of the macros, when
144 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
146 * The system_filter_user option now defaults to the Exim run-time user,
147 rather than root. You can still set it explicitly to root and this
148 can be done with prior versions too, letting you roll versions
149 without needing to change this configuration option.
151 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
152 defined at build time.
158 1. Experimental Yahoo! Domainkeys support has been dropped in this release.
159 It has been superceded by a native implementation of its successor DKIM.
161 2. Up to version 4.69, Exim came with an embedded version of the PCRE library.
162 As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
163 installed. Most OS distributions have ready-made library and development
170 1. The internal implementation of the database keys that are used for ACL
171 ratelimiting has been tidied up. This means that an update to 4.68 might cause
172 Exim to "forget" previous rates that it had calculated, and reset them to zero.
178 1. Callouts were setting the name used for EHLO/HELO from $smtp_active_
179 hostname. This is wrong, because it relates to the incoming message (and
180 probably the interface on which it is arriving) and not to the outgoing
181 callout (which could be using a different interface). This has been
182 changed to use the value of the helo_data option from the smtp transport
183 instead - this is what is used when a message is actually being sent. If
184 there is no remote transport (possible with a router that sets up host
185 addresses), $smtp_active_hostname is used. This change is mentioned here in
186 case somebody is relying on the use of $smtp_active_hostname.
188 2. A bug has been fixed that might just possibly be something that is relied on
189 in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
190 empty string (that is {}) was being interpreted as if it was {0} and therefore
191 treated as the number zero. From release 4.64, such strings cause an error
192 because a decimal number, possibly followed by K or M, is required (as has
193 always been documented).
195 3. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
196 Exim's performance. Unfortunately, this has the side effect of being slightly
197 non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
198 one of these earlier versions and you use GnuTLS, you must remove the file
199 called gnutls-params in Exim's spool directory. If you don't do this, you will
202 TLS error on connection from ... (DH params import): Base64 decoding error.
204 Removing the file causes Exim to recompute the relevant encryption parameters
205 and cache them in the new format that was introduced for release 4.51 (May
206 2005). If you are upgrading from release 4.51 or later, there should be no
213 When an SMTP error message is specified in a "message" modifier in an ACL, or
214 in a :fail: or :defer: message in a redirect router, Exim now checks the start
215 of the message for an SMTP error code. This consists of three digits followed
216 by a space, optionally followed by an extended code of the form n.n.n, also
217 followed by a space. If this is the case and the very first digit is the same
218 as the default error code, the code from the message is used instead. If the
219 very first digit is incorrect, a panic error is logged, and the default code is
220 used. This is an incompatible change, but it is not expected to affect many (if
221 any) configurations. It is possible to suppress the use of the supplied code in
222 a redirect router by setting the smtp_error_code option false. In this case,
223 any SMTP code is quietly ignored.
229 1. The default number of ACL variables of each type has been increased to 20,
230 and it's possible to compile Exim with more. You can safely upgrade to this
231 release if you already have messages on the queue with saved ACL variable
232 values. However, if you downgrade from this release with messages on the queue,
233 any saved ACL values they may have will be lost.
235 2. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
241 There was a problem with 4.52/TF/02 in that a "name=" option on control=
242 submission terminated at the next slash, thereby not allowing for slashes in
243 the name. This has been changed so that "name=" takes the rest of the string as
244 its data. It must therefore be the last option.
250 If you are using the experimental Domain Keys support, you must upgrade to
251 at least libdomainkeys 0.67 in order to run this release of Exim.
257 1. The format in which GnuTLS parameters are cached (in the file gnutls-params
258 in the spool directory) has been changed. The new format can also be generated
259 externally, so it is now possible to update the values from outside Exim. This
260 has been implemented in an upwards, BUT NOT downwards, compatible manner.
261 Upgrading should be seamless: when Exim finds that it cannot understand an
262 existing cache file, it generates new parameters and writes them to the cache
263 in the new format. If, however, you downgrade from 4.51 to a previous release,
264 you MUST delete the gnutls-params file in the spool directory, because the
265 older Exim will not recognize the new format.
267 2. When doing a callout as part of verifying an address, Exim was not paying
268 attention to any local part prefix or suffix that was matched by the router
269 that accepted the address. It now behaves in the same way as it does for
270 delivery: the affixes are removed from the local part unless
271 rcpt_include_affixes is set on the transport. If you have a configuration that
272 uses prefixes or suffixes on addresses that could be used for callouts, and you
273 want the affixes to be retained, you must make sure that rcpt_include_affixes
274 is set on the transport.
276 3. Bounce and delay warning messages no longer contain details of delivery
277 errors, except for explicit messages (e.g. generated by :fail:) and SMTP
278 responses from remote hosts.
284 The exicyclog script has been updated to use three-digit numbers in rotated log
285 files if the maximum number to keep is greater than 99. If you are already
286 keeping more than 99, there will be an incompatible change when you upgrade.
287 You will probably want to rename your old log files to the new form before
288 running the new exicyclog.
294 RFC 3848 specifies standard names for the "with" phrase in Received: header
295 lines when AUTH and/or TLS are in use. This is the "received protocol"
296 field. Exim used to use "asmtp" for authenticated SMTP, without any
297 indication (in the protocol name) for TLS use. Now it follows the RFC and
298 uses "esmtpa" if the connection is authenticated, "esmtps" if it is
299 encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
300 appear in log lines as well as in Received: header lines.
306 Change 4.31/2 gave problems to data ACLs and local_scan() functions that
307 expected to see a Received: header. I have changed to yet another scheme. The
308 Received: header is now generated after the body is received, but before the
309 ACL or local_scan() is called. After they have run, the timestamp in the
310 Received: header is updated.
312 Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
313 which is lucky, since I decided it was a bug fix.
319 If an expansion in a condition on a "warn" statement fails because a lookup
320 defers, the "warn" statement is abandoned, and the next ACL statement is
321 processed. Previously this caused the whole ACL to be aborted.
327 Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
328 verification now uses <> in the MAIL command by default, as it did before. A
329 new callout option, "use_sender", has been added to request the other
336 1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
337 or greater. The interface to the obsolete 0.8.x releases is no longer
338 supported. There is one externally visible change: the format for the
339 display of Distinguished Names now uses commas as a separator rather than a
340 slash. This is to comply with RFC 2253.
342 2. When a message is received, the Received: header line is now generated when
343 reception is complete, instead of at the start of reception. For messages
344 that take a long time to come in, this changes the meaning of the timestamp.
345 There are several side-effects of this change:
347 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
348 the logged header lines no longer include the local Received: line,
349 because it has not yet been created. If the message is a non-SMTP one,
350 and the error is processed by sending a message to the sender, the copy
351 of the original message that is returned does not have an added
354 (b) When a filter file is tested using -bf, no additional Received: header
355 is added to the test message. After some thought, I decided that this
358 The contents of $received_for are not affected by this change. This
359 variable still contains the single recipient of a message, copied after
360 addresses have been rewritten, but before local_scan() is run.
362 2. Recipient callout verification, like sender verification, was using <> in
363 the MAIL FROM command. This isn't really the right thing, since the actual
364 sender may affect whether the remote host accepts the recipient or not. I
365 have changed it to use the actual sender in the callout; this means that
366 the cache record is now keyed on a recipient/sender pair, not just the
367 recipient address. There doesn't seem to be a real danger of callout loops,
368 since a callout by the remote host to check the sender would use <>.
374 1. I have abolished timeout_DNS as an error that can be detected in retry
375 rules, because it has never worked. Despite the fact that it has been
376 documented since at least release 1.62, there was no code to support it.
377 If you have used it in your retry rules, you will now get a warning message
378 to the log and panic log. It is now treated as plain "timeout".
380 2. After discussion on the mailing list, Exim no longer adds From:, Date:, or
381 Message-Id: header lines to messages that do not originate locally, that is,
382 messages that have an associated sending host address.
384 3. When looking up a host name from an IP address, Exim now tries the DNS
385 first, and only if that fails does it use gethostbyaddr() (or equivalent).
386 This change was made because on some OS, not all the names are given for
387 addresses with multiple PTR records via the gethostbyaddr() interface. The
388 order of lookup can be changed by setting host_lookup_order.
394 1. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
395 that cannot be overridden. The default in the distributed EDITME is "root".
396 If for some reason you were (against advice) running deliveries as root, you
397 will have to ensure that FIXED_NEVER_USERS is not set in your
400 2. The ${quote: operator now quotes an empty string, which it did not before.
402 3. Version 4.23 saves the contents of the ACL variables with the message, so
403 that they can be used later. If one of these variables contains a newline,
404 there will be a newline character in the spool that will not be interpreted
405 correctely by a previous version of Exim. (Exim ignores keyed spool file
406 items that it doesn't understand - precisely for this kind of problem - but
407 it expects them all to be on one line.)
409 So the bottom line is: if you have newlines in your ACL variables, you
410 cannot retreat from 4.23.
416 1. The idea of the "warn" ACL verb is that it adds a header or writes to the
417 log only when "message" or "log_message" are set. However, if one of the
418 conditions was an address verification, or a call to a nested ACL, the
419 messages generated by the underlying test were being passed through. This
420 no longer happens. The underlying message is available in $acl_verify_
421 message for both "message" and "log_message" expansions, so it can be
422 passed through if needed.
424 2. The way that the $h_ (and $header_) expansions work has been changed by the
425 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
426 until release 4.30, then the manual) for full details. Briefly, there are
429 $rh_xxx: and $rheader_xxx: give the original content of the header
430 line(s), with no processing at all.
432 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
433 then decode base64 or quoted-printable "words" within the header text,
434 but do not do charset translation.
436 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
437 standard character set.
439 If you have previously been using $h_ expansions to access the raw
440 characters, you should change to $rh_ instead.
442 3. When Exim creates an RFC 2047 encoded word in a header line, it labels it
443 with the default character set from the headers_charset option instead of
444 always using iso-8859-1.
446 4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
447 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
448 called TMPDIR, and if it finds it is different, it changes its value.
450 5. Following a discussion on the list, the rules by which Exim recognises line
451 endings on incoming messages have been changed. The -dropcr and drop_cr
452 options are now no-ops, retained only for backwards compatibility. The
453 following line terminators are recognized: LF CRLF CR. However, special
454 processing applies to CR:
456 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
457 nor a local message in the state where . is a terminator.
459 (ii) If a bare CR is encountered in a header line, an extra space is added
460 after the line terminator so as not to end the header. The reasoning
461 behind this is that bare CRs in header lines are most likely either
462 to be mistakes, or people trying to play silly games.
464 6. The code for using daemon_smtp_port, local_interfaces, and the -oX options
465 has been reorganized. It is supposed to be backwards compatible, but it is
466 mentioned here just in case I've screwed up.
473 1. I have tidied and re-organized the code that uses alarm() for imposing time
474 limits on various things. It shouldn't affect anything, but if you notice
475 processes getting stuck, it may be that I've broken something.
477 2. The "arguments" log selector now also logs the current working directory
480 3. An incompatible change has been made to the appendfile transport. This
481 affects the case when it is used for file deliveries that are set up by
482 .forward and filter files. Previously, any settings of the "file" or
483 "directory" options were ignored. It is hoped that, like the address_file
484 transport in the default configuration, these options were never in fact set
485 on such transports, because they were of no use.
487 Now, if either of these options is set, it is used. The path that is passed
488 by the router is in $address_file (this is not new), so it can be used as
489 part of a longer path, or modified in any other way that expansion permits.
491 If neither "file" nor "directory" is set, the behaviour is unchanged.
493 4. Related to the above: in a filter, if a "save" command specifies a non-
494 absolute path, the value of $home/ is pre-pended. This no longer happens if
495 $home is unset or is set to an empty string.
497 5. Multiple file deliveries from a filter or .forward file can never be
498 batched; the value of batch_max on the transport is ignored for file
499 deliveries. I'm assuming that nobody ever actually set batch_max on the
500 address_file transport - it would have had odd effects previously.
502 6. DESTDIR is the more common variable that ROOT for use when installing
503 software under a different root filing system. The Exim install script now
504 recognizes DESTDIR first; if it is not set, ROOT is used.
506 7. If DESTDIR is set when installing Exim, it no longer prepends its value to
507 the path of the system aliases file that appears in the default
508 configuration (when a default configuration is installed). If an aliases
509 file is actually created, its name *does* use the prefix.
515 1. The default for the maximum number of unknown SMTP commands that Exim will
516 accept before dropping a connection has been reduced from 5 to 3. However, you
517 can now change the value by setting smtp_max_unknown_commands.
519 2. The ${quote: operator has been changed so that it turns newline and carriage
520 return characters into \n and \r, respectively.
522 3. The file names used for maildir messages now include the microsecond time
523 fraction as well as the time in seconds, to cope with systems where the process
524 id can be re-used within the same second. The format is now
526 <time>.H<microsec>P<pid>.<host>
528 This should be a compatible change, but is noted here just in case.
530 4. The rules for creating message ids have changed, to cope with systems where
531 the process id can be re-used within the same second. The format, however, is
532 unchanged, so this should not cause any problems, except as noted in the next
535 5. The maximum value for localhost_number has been reduced from 255 to 16, in
536 order to implement the new message id rules. For operating systems that have
537 case-insensitive file systems (Cygwin and Darwin), the limit is 10.
539 6. verify = header_syntax was allowing unqualified addresses in all cases. Now
540 it allows them only for locally generated messages and from hosts that match
541 sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
543 7. For reasons lost in the mists of time, when a pipe transport was run, the
544 environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
545 form used in Message-ID: header lines). The 'E' has been removed.
551 1. The handling of lines in the configuration file has changed. Previously,
552 macro expansion was applied to logical lines, after continuations had been
553 joined on. This meant that it could not be used in .include lines, which are
554 handled as physical rather than logical lines. Macro expansion is now done on
555 physical lines rather than logical lines. This means there are two
558 (a) A macro that expands to # to turn a line into a comment now applies only
559 to the physical line where it appears. Previously, it would have caused
560 any following continuations also to be ignored.
562 (b) A macro name can no longer be split over the boundary between a line and
563 its continuation. Actually, this is more of a bug fix. :-)
565 2. The -D command line option must now all be within one command line item.
566 This makes it possible to use -D to set a macro to the empty string by commands
572 Previously, these items would have moved on to the next item on the command
573 line. To include spaces in a macro definition item, quotes must be used, in
574 which case you can also have spaces after -D and surrounding the equals. For
577 exim '-D ABC = something' ...
579 3. The way that addresses that redirect to themselves are handled has been
580 changed, in order to fix an obscure bug. This should not cause any problems
581 except in the case of wanting to go back from a 4.11 (or later) release to an
582 earlier release. If there are undelivered messages on the spool that contain
583 addresses which redirect to themselves, and the redirected addresses have
584 already been delivered, you might get a duplicate delivery if you revert to an
587 4. The default way of looking up IP addresses for hosts in the manualroute and
588 queryprogram routers has been changed. If "byname" or "bydns" is explicitly
589 specified, there is no change, but if no method is specified, Exim now behaves
592 First, a DNS lookup is done. If this yields anything other than
593 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
594 getipnodebyname() (or gethostbyname() on older systems) and the result of the
595 lookup is the result of that call.
597 This change has been made because it has been discovered that on some systems,
598 if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
599 returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
600 first, and only if that gives a definite "no such host" to try the local
603 5. In fixing the minor security problem with pid_file_path, I have removed some
604 backwards-compatible (undocumented) code which was present to ease conversion
605 from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
606 contain "%s", which was replaced by the port number for daemons listening on
607 non-standard ports. In Exim 4, such daemons do not write a pid file. The
608 backwards compatibility feature was to replace "%s" by nothing if it occurred
609 in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
610 the problem by removing the backwards compatibility feature. Thus, if you still
611 have "%s" somewhere in a setting of pid_file_path, you should remove it.
613 6. There has been an extension to lsearch files. The keys in these files may
614 now be quoted in order to allow for whitespace and colons in them. This means
615 that if you were previously using keys that began with a doublequote, you will
616 now have to wrap them with extra quotes and escape the internal quotes. The
617 possibility that anybody is actually doing this seems extremely remote, but it
618 is documented just in case.
624 The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
625 to better reflect its function. The OS-specific files have been updated. Only
626 if you have explicitly set this in your Makefile (highly unlikely) do you need
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