More GnuTLS cleanups/fixes.
[exim.git] / src / README.UPDATING
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...
6
7
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. *
16 * *
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 **************************************************************************
23
24
25 The rest of this document contains information about changes in 4.xx releases
26 that might affect a running system.
27
28
29 Exim version 4.80
30 -----------------
31
32 * BEWARE backwards-incompatible changes in SSL libraries, thus the version
33 bump. See points below for details.
34
35 * The value of $tls_peerdn is now print-escaped when written to the spool file
36 in a -tls_peerdn line, and unescaped when read back in. We received reports
37 of values with embedded newlines, which caused spool file corruption.
38
39 If you have a corrupt spool file and you wish to recover the contents after
40 upgrading, then lock the message, replace the new-lines that should be part
41 of the -tls_peerdn line with the two-character sequence \n and then unlock
42 the message. No tool has been provided as we believe this is a rare
43 occurence.
44
45 * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built
46 against 1.0.1a then you will get a warning message and the
47 "openssl_options" value will not parse "no_tlsv1_1": the value changes
48 incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a
49 is infelicitous. We advise avoiding 1.0.1a.
50
51 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
52
53 COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
54 "+dont_insert_empty_fragments". We default to unset. That old default was
55 grandfathered in from before openssl_options became a configuration option.
56 Empty fragments are inserted by default through TLS1.0, to partially defend
57 against certain attacks; TLS1.1+ change the protocol so that this is not
58 needed. The DIEF SSL option was required for some old releases of mail
59 clients which did not gracefully handle the empty fragments, and was
60 initially set in Exim release 4.31 (see ChangeLog, item 37).
61
62 If you still have affected mail-clients, and you see SSL protocol failures
63 with this release of Exim, set:
64 openssl_options = +dont_insert_empty_fragments
65 in the main section of your Exim configuration file. You're trading off
66 security for compatibility. Exim is now defaulting to higher security and
67 rewarding more modern clients.
68
69 * Ldap lookups returning multi-valued attributes now separate the attributes
70 with only a comma, not a comma-space sequence. Also, an actual comma within
71 a returned attribute is doubled. This makes it possible to parse the
72 attribute as a comma-separated list. Note the distinction from multiple
73 attributes being returned, where each one is a name=value pair.
74
75 * accept_8bitmime now defaults on, which is not RFC compliant but is better
76 suited to today's Internet. See http://cr.yp.to/smtp/8bitmime.html for a
77 sane rationale. Those who wish to be strictly RFC compliant, or know that
78 they need to talk to servers that are not 8-bit-clean, now need to take
79 explicit configuration action to default this option off. This is not a
80 new option, you can safely force it off before upgrading, to decouple
81 configuration changes from the binary upgrade while remaining RFC compliant.
82
83 * The GnuTLS support has been mostly rewritten, to use 2.12.x APIs. As part
84 of this, these three options are no longer supported:
85
86 gnutls_require_kx
87 gnutls_require_mac
88 gnutls_require_protocols
89
90 Their functionality is entirely subsumed into tls_require_ciphers, which is
91 no longer parsed apart by Exim but is instead given to
92 gnutls_priority_init(3), which is no longer an Exim list. See:
93
94 http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html
95
96 for fuller documentation of the strings parsed. The three gnutls_require_*
97 options are still parsed by Exim and, for this release, silently ignored.
98 A future release will add warnings, before a later still release removes
99 parsing entirely and the presence of the options will be a configuration
100 error.
101
102 Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains.
103 A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may
104 re-enable support, but this is not supported by the Exim maintainers.
105 Our test suite no longer includes MD5-based certificates.
106
107 This rewrite means that Exim will continue to build against GnuTLS in the
108 future, brings Exim closer to other GnuTLS applications and lets us add
109 support for SNI and other features more readily. We regret that it wasn't
110 feasible to retain the three dropped options.
111
112
113 Exim version 4.77
114 -----------------
115
116 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
117 if supported by your GnuTLS library. Use the existing
118 "gnutls_require_protocols" option to downgrade this if that will be a
119 problem. Prior to this release, supported values were "TLS1" and "SSL3",
120 so you should be able to update configuration prior to update.
121
122 [nb: gnutls_require_protocols removed in Exim 4.80, instead use
123 tls_require_ciphers to provide a priority string; see notes above]
124
125 * The match_<type>{string1}{string2} expansion conditions no longer subject
126 string2 to string expansion, unless Exim was built with the new
127 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
128 insecure configurations that way. If you need the functionality and turn on
129 that build option, please let the developers know, and know why, so we can
130 try to provide a safer mechanism for you.
131
132 The match{}{} expansion condition (for regular expressions) is NOT affected.
133 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
134 change is that a '$' appearing in s2 will not trigger expansion, but instead
135 will be treated as a literal $ sign; the effect is very similar to having
136 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
137 uses $expansions then those _will_ be processed as normal. It is only the
138 point at which s2 is read where expansion is inhibited.
139
140 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
141 If you are testing if the address in s1 occurs in the list of items given
142 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
143 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
144
145
146 Exim version 4.74
147 -----------------
148
149 * The integrated support for dynamically loadable lookup modules has an ABI
150 change from the modules supported by some OS vendors through an unofficial
151 patch. Don't try to mix & match.
152
153 * Some parts of the build system are now beginning to assume that the host
154 environment is POSIX. If you're building on a system where POSIX tools are
155 not the default, you might have an easier time if you switch to the POSIX
156 tools. Feel free to report non-POSIX issues as a request for a feature
157 enhancement, but if the POSIX variants are available then the fix will
158 probably just involve some coercion. See the README instructions for
159 building on such hosts.
160
161
162 Exim version 4.73
163 -----------------
164
165 * The Exim run-time user can no longer be root; this was always
166 strongly discouraged, but is now prohibited both at build and
167 run-time. If you need Exim to run routinely as root, you'll need to
168 patch the source and accept the risk. Here be dragons.
169
170 * Exim will no longer accept a configuration file owned by the Exim
171 run-time user, unless that account is explicitly the value in
172 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
173 files are not writeable by other accounts.
174
175 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
176 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
177 Two new build options mitigate this.
178
179 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
180 files that are trusted to be selected by the Exim user; one per line.
181 This is the recommended approach going forward.
182
183 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
184 the Exim run-time user may safely pass without dropping privileges.
185 Because changes to this involve a recompile, this is not the recommended
186 approach but may ease transition. The values of the macros, when
187 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
188
189 * The system_filter_user option now defaults to the Exim run-time user,
190 rather than root. You can still set it explicitly to root and this
191 can be done with prior versions too, letting you roll versions
192 without needing to change this configuration option.
193
194 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
195 defined at build time.
196
197
198 Exim version 4.70
199 -----------------
200
201 1. Experimental Yahoo! Domainkeys support has been dropped in this release.
202 It has been superceded by a native implementation of its successor DKIM.
203
204 2. Up to version 4.69, Exim came with an embedded version of the PCRE library.
205 As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
206 installed. Most OS distributions have ready-made library and development
207 packages.
208
209
210 Exim version 4.68
211 -----------------
212
213 1. The internal implementation of the database keys that are used for ACL
214 ratelimiting has been tidied up. This means that an update to 4.68 might cause
215 Exim to "forget" previous rates that it had calculated, and reset them to zero.
216
217
218 Exim version 4.64
219 -----------------
220
221 1. Callouts were setting the name used for EHLO/HELO from $smtp_active_
222 hostname. This is wrong, because it relates to the incoming message (and
223 probably the interface on which it is arriving) and not to the outgoing
224 callout (which could be using a different interface). This has been
225 changed to use the value of the helo_data option from the smtp transport
226 instead - this is what is used when a message is actually being sent. If
227 there is no remote transport (possible with a router that sets up host
228 addresses), $smtp_active_hostname is used. This change is mentioned here in
229 case somebody is relying on the use of $smtp_active_hostname.
230
231 2. A bug has been fixed that might just possibly be something that is relied on
232 in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
233 empty string (that is {}) was being interpreted as if it was {0} and therefore
234 treated as the number zero. From release 4.64, such strings cause an error
235 because a decimal number, possibly followed by K or M, is required (as has
236 always been documented).
237
238 3. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
239 Exim's performance. Unfortunately, this has the side effect of being slightly
240 non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
241 one of these earlier versions and you use GnuTLS, you must remove the file
242 called gnutls-params in Exim's spool directory. If you don't do this, you will
243 see this error:
244
245 TLS error on connection from ... (DH params import): Base64 decoding error.
246
247 Removing the file causes Exim to recompute the relevant encryption parameters
248 and cache them in the new format that was introduced for release 4.51 (May
249 2005). If you are upgrading from release 4.51 or later, there should be no
250 problem.
251
252
253 Exim version 4.63
254 -----------------
255
256 When an SMTP error message is specified in a "message" modifier in an ACL, or
257 in a :fail: or :defer: message in a redirect router, Exim now checks the start
258 of the message for an SMTP error code. This consists of three digits followed
259 by a space, optionally followed by an extended code of the form n.n.n, also
260 followed by a space. If this is the case and the very first digit is the same
261 as the default error code, the code from the message is used instead. If the
262 very first digit is incorrect, a panic error is logged, and the default code is
263 used. This is an incompatible change, but it is not expected to affect many (if
264 any) configurations. It is possible to suppress the use of the supplied code in
265 a redirect router by setting the smtp_error_code option false. In this case,
266 any SMTP code is quietly ignored.
267
268
269 Exim version 4.61
270 -----------------
271
272 1. The default number of ACL variables of each type has been increased to 20,
273 and it's possible to compile Exim with more. You can safely upgrade to this
274 release if you already have messages on the queue with saved ACL variable
275 values. However, if you downgrade from this release with messages on the queue,
276 any saved ACL values they may have will be lost.
277
278 2. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
279
280
281 Exim version 4.54
282 -----------------
283
284 There was a problem with 4.52/TF/02 in that a "name=" option on control=
285 submission terminated at the next slash, thereby not allowing for slashes in
286 the name. This has been changed so that "name=" takes the rest of the string as
287 its data. It must therefore be the last option.
288
289
290 Version 4.53
291 ------------
292
293 If you are using the experimental Domain Keys support, you must upgrade to
294 at least libdomainkeys 0.67 in order to run this release of Exim.
295
296
297 Version 4.51
298 ------------
299
300 1. The format in which GnuTLS parameters are cached (in the file gnutls-params
301 in the spool directory) has been changed. The new format can also be generated
302 externally, so it is now possible to update the values from outside Exim. This
303 has been implemented in an upwards, BUT NOT downwards, compatible manner.
304 Upgrading should be seamless: when Exim finds that it cannot understand an
305 existing cache file, it generates new parameters and writes them to the cache
306 in the new format. If, however, you downgrade from 4.51 to a previous release,
307 you MUST delete the gnutls-params file in the spool directory, because the
308 older Exim will not recognize the new format.
309
310 2. When doing a callout as part of verifying an address, Exim was not paying
311 attention to any local part prefix or suffix that was matched by the router
312 that accepted the address. It now behaves in the same way as it does for
313 delivery: the affixes are removed from the local part unless
314 rcpt_include_affixes is set on the transport. If you have a configuration that
315 uses prefixes or suffixes on addresses that could be used for callouts, and you
316 want the affixes to be retained, you must make sure that rcpt_include_affixes
317 is set on the transport.
318
319 3. Bounce and delay warning messages no longer contain details of delivery
320 errors, except for explicit messages (e.g. generated by :fail:) and SMTP
321 responses from remote hosts.
322
323
324 Version 4.50
325 ------------
326
327 The exicyclog script has been updated to use three-digit numbers in rotated log
328 files if the maximum number to keep is greater than 99. If you are already
329 keeping more than 99, there will be an incompatible change when you upgrade.
330 You will probably want to rename your old log files to the new form before
331 running the new exicyclog.
332
333
334 Version 4.42
335 ------------
336
337 RFC 3848 specifies standard names for the "with" phrase in Received: header
338 lines when AUTH and/or TLS are in use. This is the "received protocol"
339 field. Exim used to use "asmtp" for authenticated SMTP, without any
340 indication (in the protocol name) for TLS use. Now it follows the RFC and
341 uses "esmtpa" if the connection is authenticated, "esmtps" if it is
342 encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
343 appear in log lines as well as in Received: header lines.
344
345
346 Version 4.34
347 ------------
348
349 Change 4.31/2 gave problems to data ACLs and local_scan() functions that
350 expected to see a Received: header. I have changed to yet another scheme. The
351 Received: header is now generated after the body is received, but before the
352 ACL or local_scan() is called. After they have run, the timestamp in the
353 Received: header is updated.
354
355 Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
356 which is lucky, since I decided it was a bug fix.
357
358
359 Version 4.33
360 ------------
361
362 If an expansion in a condition on a "warn" statement fails because a lookup
363 defers, the "warn" statement is abandoned, and the next ACL statement is
364 processed. Previously this caused the whole ACL to be aborted.
365
366
367 Version 4.32
368 ------------
369
370 Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
371 verification now uses <> in the MAIL command by default, as it did before. A
372 new callout option, "use_sender", has been added to request the other
373 behaviour.
374
375
376 Version 4.31
377 ------------
378
379 1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
380 or greater. The interface to the obsolete 0.8.x releases is no longer
381 supported. There is one externally visible change: the format for the
382 display of Distinguished Names now uses commas as a separator rather than a
383 slash. This is to comply with RFC 2253.
384
385 2. When a message is received, the Received: header line is now generated when
386 reception is complete, instead of at the start of reception. For messages
387 that take a long time to come in, this changes the meaning of the timestamp.
388 There are several side-effects of this change:
389
390 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
391 the logged header lines no longer include the local Received: line,
392 because it has not yet been created. If the message is a non-SMTP one,
393 and the error is processed by sending a message to the sender, the copy
394 of the original message that is returned does not have an added
395 Received: line.
396
397 (b) When a filter file is tested using -bf, no additional Received: header
398 is added to the test message. After some thought, I decided that this
399 is a bug fix.
400
401 The contents of $received_for are not affected by this change. This
402 variable still contains the single recipient of a message, copied after
403 addresses have been rewritten, but before local_scan() is run.
404
405 2. Recipient callout verification, like sender verification, was using <> in
406 the MAIL FROM command. This isn't really the right thing, since the actual
407 sender may affect whether the remote host accepts the recipient or not. I
408 have changed it to use the actual sender in the callout; this means that
409 the cache record is now keyed on a recipient/sender pair, not just the
410 recipient address. There doesn't seem to be a real danger of callout loops,
411 since a callout by the remote host to check the sender would use <>.
412
413
414 Version 4.30
415 ------------
416
417 1. I have abolished timeout_DNS as an error that can be detected in retry
418 rules, because it has never worked. Despite the fact that it has been
419 documented since at least release 1.62, there was no code to support it.
420 If you have used it in your retry rules, you will now get a warning message
421 to the log and panic log. It is now treated as plain "timeout".
422
423 2. After discussion on the mailing list, Exim no longer adds From:, Date:, or
424 Message-Id: header lines to messages that do not originate locally, that is,
425 messages that have an associated sending host address.
426
427 3. When looking up a host name from an IP address, Exim now tries the DNS
428 first, and only if that fails does it use gethostbyaddr() (or equivalent).
429 This change was made because on some OS, not all the names are given for
430 addresses with multiple PTR records via the gethostbyaddr() interface. The
431 order of lookup can be changed by setting host_lookup_order.
432
433
434 Version 4.23
435 ------------
436
437 1. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
438 that cannot be overridden. The default in the distributed EDITME is "root".
439 If for some reason you were (against advice) running deliveries as root, you
440 will have to ensure that FIXED_NEVER_USERS is not set in your
441 Local/Makefile.
442
443 2. The ${quote: operator now quotes an empty string, which it did not before.
444
445 3. Version 4.23 saves the contents of the ACL variables with the message, so
446 that they can be used later. If one of these variables contains a newline,
447 there will be a newline character in the spool that will not be interpreted
448 correctely by a previous version of Exim. (Exim ignores keyed spool file
449 items that it doesn't understand - precisely for this kind of problem - but
450 it expects them all to be on one line.)
451
452 So the bottom line is: if you have newlines in your ACL variables, you
453 cannot retreat from 4.23.
454
455
456 Version 4.21
457 ------------
458
459 1. The idea of the "warn" ACL verb is that it adds a header or writes to the
460 log only when "message" or "log_message" are set. However, if one of the
461 conditions was an address verification, or a call to a nested ACL, the
462 messages generated by the underlying test were being passed through. This
463 no longer happens. The underlying message is available in $acl_verify_
464 message for both "message" and "log_message" expansions, so it can be
465 passed through if needed.
466
467 2. The way that the $h_ (and $header_) expansions work has been changed by the
468 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
469 until release 4.30, then the manual) for full details. Briefly, there are
470 now three forms:
471
472 $rh_xxx: and $rheader_xxx: give the original content of the header
473 line(s), with no processing at all.
474
475 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
476 then decode base64 or quoted-printable "words" within the header text,
477 but do not do charset translation.
478
479 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
480 standard character set.
481
482 If you have previously been using $h_ expansions to access the raw
483 characters, you should change to $rh_ instead.
484
485 3. When Exim creates an RFC 2047 encoded word in a header line, it labels it
486 with the default character set from the headers_charset option instead of
487 always using iso-8859-1.
488
489 4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
490 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
491 called TMPDIR, and if it finds it is different, it changes its value.
492
493 5. Following a discussion on the list, the rules by which Exim recognises line
494 endings on incoming messages have been changed. The -dropcr and drop_cr
495 options are now no-ops, retained only for backwards compatibility. The
496 following line terminators are recognized: LF CRLF CR. However, special
497 processing applies to CR:
498
499 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
500 nor a local message in the state where . is a terminator.
501
502 (ii) If a bare CR is encountered in a header line, an extra space is added
503 after the line terminator so as not to end the header. The reasoning
504 behind this is that bare CRs in header lines are most likely either
505 to be mistakes, or people trying to play silly games.
506
507 6. The code for using daemon_smtp_port, local_interfaces, and the -oX options
508 has been reorganized. It is supposed to be backwards compatible, but it is
509 mentioned here just in case I've screwed up.
510
511
512
513 Version 4.20
514 ------------
515
516 1. I have tidied and re-organized the code that uses alarm() for imposing time
517 limits on various things. It shouldn't affect anything, but if you notice
518 processes getting stuck, it may be that I've broken something.
519
520 2. The "arguments" log selector now also logs the current working directory
521 when Exim is called.
522
523 3. An incompatible change has been made to the appendfile transport. This
524 affects the case when it is used for file deliveries that are set up by
525 .forward and filter files. Previously, any settings of the "file" or
526 "directory" options were ignored. It is hoped that, like the address_file
527 transport in the default configuration, these options were never in fact set
528 on such transports, because they were of no use.
529
530 Now, if either of these options is set, it is used. The path that is passed
531 by the router is in $address_file (this is not new), so it can be used as
532 part of a longer path, or modified in any other way that expansion permits.
533
534 If neither "file" nor "directory" is set, the behaviour is unchanged.
535
536 4. Related to the above: in a filter, if a "save" command specifies a non-
537 absolute path, the value of $home/ is pre-pended. This no longer happens if
538 $home is unset or is set to an empty string.
539
540 5. Multiple file deliveries from a filter or .forward file can never be
541 batched; the value of batch_max on the transport is ignored for file
542 deliveries. I'm assuming that nobody ever actually set batch_max on the
543 address_file transport - it would have had odd effects previously.
544
545 6. DESTDIR is the more common variable that ROOT for use when installing
546 software under a different root filing system. The Exim install script now
547 recognizes DESTDIR first; if it is not set, ROOT is used.
548
549 7. If DESTDIR is set when installing Exim, it no longer prepends its value to
550 the path of the system aliases file that appears in the default
551 configuration (when a default configuration is installed). If an aliases
552 file is actually created, its name *does* use the prefix.
553
554
555 Version 4.14
556 ------------
557
558 1. The default for the maximum number of unknown SMTP commands that Exim will
559 accept before dropping a connection has been reduced from 5 to 3. However, you
560 can now change the value by setting smtp_max_unknown_commands.
561
562 2. The ${quote: operator has been changed so that it turns newline and carriage
563 return characters into \n and \r, respectively.
564
565 3. The file names used for maildir messages now include the microsecond time
566 fraction as well as the time in seconds, to cope with systems where the process
567 id can be re-used within the same second. The format is now
568
569 <time>.H<microsec>P<pid>.<host>
570
571 This should be a compatible change, but is noted here just in case.
572
573 4. The rules for creating message ids have changed, to cope with systems where
574 the process id can be re-used within the same second. The format, however, is
575 unchanged, so this should not cause any problems, except as noted in the next
576 item.
577
578 5. The maximum value for localhost_number has been reduced from 255 to 16, in
579 order to implement the new message id rules. For operating systems that have
580 case-insensitive file systems (Cygwin and Darwin), the limit is 10.
581
582 6. verify = header_syntax was allowing unqualified addresses in all cases. Now
583 it allows them only for locally generated messages and from hosts that match
584 sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
585
586 7. For reasons lost in the mists of time, when a pipe transport was run, the
587 environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
588 form used in Message-ID: header lines). The 'E' has been removed.
589
590
591 Version 4.11
592 ------------
593
594 1. The handling of lines in the configuration file has changed. Previously,
595 macro expansion was applied to logical lines, after continuations had been
596 joined on. This meant that it could not be used in .include lines, which are
597 handled as physical rather than logical lines. Macro expansion is now done on
598 physical lines rather than logical lines. This means there are two
599 incompatibilities:
600
601 (a) A macro that expands to # to turn a line into a comment now applies only
602 to the physical line where it appears. Previously, it would have caused
603 any following continuations also to be ignored.
604
605 (b) A macro name can no longer be split over the boundary between a line and
606 its continuation. Actually, this is more of a bug fix. :-)
607
608 2. The -D command line option must now all be within one command line item.
609 This makes it possible to use -D to set a macro to the empty string by commands
610 such as
611
612 exim -DABC ...
613 exim -DABC= ...
614
615 Previously, these items would have moved on to the next item on the command
616 line. To include spaces in a macro definition item, quotes must be used, in
617 which case you can also have spaces after -D and surrounding the equals. For
618 example:
619
620 exim '-D ABC = something' ...
621
622 3. The way that addresses that redirect to themselves are handled has been
623 changed, in order to fix an obscure bug. This should not cause any problems
624 except in the case of wanting to go back from a 4.11 (or later) release to an
625 earlier release. If there are undelivered messages on the spool that contain
626 addresses which redirect to themselves, and the redirected addresses have
627 already been delivered, you might get a duplicate delivery if you revert to an
628 earlier Exim.
629
630 4. The default way of looking up IP addresses for hosts in the manualroute and
631 queryprogram routers has been changed. If "byname" or "bydns" is explicitly
632 specified, there is no change, but if no method is specified, Exim now behaves
633 as follows:
634
635 First, a DNS lookup is done. If this yields anything other than
636 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
637 getipnodebyname() (or gethostbyname() on older systems) and the result of the
638 lookup is the result of that call.
639
640 This change has been made because it has been discovered that on some systems,
641 if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
642 returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
643 first, and only if that gives a definite "no such host" to try the local
644 function.
645
646 5. In fixing the minor security problem with pid_file_path, I have removed some
647 backwards-compatible (undocumented) code which was present to ease conversion
648 from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
649 contain "%s", which was replaced by the port number for daemons listening on
650 non-standard ports. In Exim 4, such daemons do not write a pid file. The
651 backwards compatibility feature was to replace "%s" by nothing if it occurred
652 in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
653 the problem by removing the backwards compatibility feature. Thus, if you still
654 have "%s" somewhere in a setting of pid_file_path, you should remove it.
655
656 6. There has been an extension to lsearch files. The keys in these files may
657 now be quoted in order to allow for whitespace and colons in them. This means
658 that if you were previously using keys that began with a doublequote, you will
659 now have to wrap them with extra quotes and escape the internal quotes. The
660 possibility that anybody is actually doing this seems extremely remote, but it
661 is documented just in case.
662
663
664 Version 4.10
665 ------------
666
667 The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
668 to better reflect its function. The OS-specific files have been updated. Only
669 if you have explicitly set this in your Makefile (highly unlikely) do you need
670 to change anything.
671
672 ****