Guard TLS SNI callback define better.
[exim.git] / src / README.UPDATING
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1This document contains detailed information about incompatibilities that might
2be encountered when upgrading from one release of Exim to another. The
3information is in reverse order of release numbers. Mostly these are relatively
4small points, and the configuration file is normally upwards compatible, but
5there 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
25The rest of this document contains information about changes in 4.xx releases
26that might affect a running system.
2eda48c6 27
e6acf885 28
83e2f8a2 29Exim version 4.80
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30-----------------
31
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32 * BEWARE backwards-incompatible changes in SSL libraries, thus the version
33 bump. See points below for details.
34
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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
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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
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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
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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.
c80c5570 74
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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
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83 * The GnuTLS support has been mostly rewritten, to use APIs which don't cause
84 deprecation warnings in GnuTLS 2.12.x. As part of this, these three options
85 are no longer supported:
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86
87 gnutls_require_kx
88 gnutls_require_mac
89 gnutls_require_protocols
90
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91 Their functionality is entirely subsumed into tls_require_ciphers. In turn,
92 tls_require_ciphers is no longer an Exim list and is not parsed by Exim, but
93 is instead given to gnutls_priority_init(3), which expects a priority string;
94 this behaviour is much closer to the OpenSSL behaviour. See:
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95
96 http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html
97
98 for fuller documentation of the strings parsed. The three gnutls_require_*
99 options are still parsed by Exim and, for this release, silently ignored.
100 A future release will add warnings, before a later still release removes
101 parsing entirely and the presence of the options will be a configuration
102 error.
103
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104 Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains.
105 A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may
106 re-enable support, but this is not supported by the Exim maintainers.
107 Our test suite no longer includes MD5-based certificates.
108
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109 This rewrite means that Exim will continue to build against GnuTLS in the
110 future, brings Exim closer to other GnuTLS applications and lets us add
111 support for SNI and other features more readily. We regret that it wasn't
112 feasible to retain the three dropped options.
113
dec5017e 114
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115Exim version 4.77
116-----------------
117
118 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
119 if supported by your GnuTLS library. Use the existing
120 "gnutls_require_protocols" option to downgrade this if that will be a
121 problem. Prior to this release, supported values were "TLS1" and "SSL3",
122 so you should be able to update configuration prior to update.
123
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124 [nb: gnutls_require_protocols removed in Exim 4.80, instead use
125 tls_require_ciphers to provide a priority string; see notes above]
126
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127 * The match_<type>{string1}{string2} expansion conditions no longer subject
128 string2 to string expansion, unless Exim was built with the new
129 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
130 insecure configurations that way. If you need the functionality and turn on
131 that build option, please let the developers know, and know why, so we can
132 try to provide a safer mechanism for you.
133
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134 The match{}{} expansion condition (for regular expressions) is NOT affected.
135 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
136 change is that a '$' appearing in s2 will not trigger expansion, but instead
137 will be treated as a literal $ sign; the effect is very similar to having
138 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
139 uses $expansions then those _will_ be processed as normal. It is only the
140 point at which s2 is read where expansion is inhibited.
141
142 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
143 If you are testing if the address in s1 occurs in the list of items given
144 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
145 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
146
c566dd90 147
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148Exim version 4.74
149-----------------
150
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151 * The integrated support for dynamically loadable lookup modules has an ABI
152 change from the modules supported by some OS vendors through an unofficial
153 patch. Don't try to mix & match.
154
155 * Some parts of the build system are now beginning to assume that the host
156 environment is POSIX. If you're building on a system where POSIX tools are
157 not the default, you might have an easier time if you switch to the POSIX
158 tools. Feel free to report non-POSIX issues as a request for a feature
159 enhancement, but if the POSIX variants are available then the fix will
160 probably just involve some coercion. See the README instructions for
161 building on such hosts.
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162
163
164Exim version 4.73
165-----------------
166
167 * The Exim run-time user can no longer be root; this was always
168 strongly discouraged, but is now prohibited both at build and
169 run-time. If you need Exim to run routinely as root, you'll need to
170 patch the source and accept the risk. Here be dragons.
171
172 * Exim will no longer accept a configuration file owned by the Exim
173 run-time user, unless that account is explicitly the value in
174 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
a7ee5955 175 files are not writeable by other accounts.
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176
177 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
178 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
179 Two new build options mitigate this.
180
181 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
182 files that are trusted to be selected by the Exim user; one per line.
183 This is the recommended approach going forward.
184
185 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
186 the Exim run-time user may safely pass without dropping privileges.
187 Because changes to this involve a recompile, this is not the recommended
188 approach but may ease transition. The values of the macros, when
43236f35 189 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
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190
191 * The system_filter_user option now defaults to the Exim run-time user,
192 rather than root. You can still set it explicitly to root and this
193 can be done with prior versions too, letting you roll versions
194 without needing to change this configuration option.
195
196 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
197 defined at build time.
198
199
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200Exim version 4.70
201-----------------
202
2031. Experimental Yahoo! Domainkeys support has been dropped in this release.
204It has been superceded by a native implementation of its successor DKIM.
205
2062. Up to version 4.69, Exim came with an embedded version of the PCRE library.
207As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
a7ee5955 208installed. Most OS distributions have ready-made library and development
2eda48c6 209packages.
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210
211
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212Exim version 4.68
213-----------------
214
2151. The internal implementation of the database keys that are used for ACL
216ratelimiting has been tidied up. This means that an update to 4.68 might cause
217Exim to "forget" previous rates that it had calculated, and reset them to zero.
218
219
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220Exim version 4.64
221-----------------
222
2231. Callouts were setting the name used for EHLO/HELO from $smtp_active_
224hostname. This is wrong, because it relates to the incoming message (and
225probably the interface on which it is arriving) and not to the outgoing
226callout (which could be using a different interface). This has been
227changed to use the value of the helo_data option from the smtp transport
228instead - this is what is used when a message is actually being sent. If
229there is no remote transport (possible with a router that sets up host
230addresses), $smtp_active_hostname is used. This change is mentioned here in
231case somebody is relying on the use of $smtp_active_hostname.
232
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2332. A bug has been fixed that might just possibly be something that is relied on
234in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
235empty string (that is {}) was being interpreted as if it was {0} and therefore
236treated as the number zero. From release 4.64, such strings cause an error
237because a decimal number, possibly followed by K or M, is required (as has
238always been documented).
239
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2403. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
241Exim's performance. Unfortunately, this has the side effect of being slightly
242non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
243one of these earlier versions and you use GnuTLS, you must remove the file
244called gnutls-params in Exim's spool directory. If you don't do this, you will
245see this error:
246
247 TLS error on connection from ... (DH params import): Base64 decoding error.
248
249Removing the file causes Exim to recompute the relevant encryption parameters
250and cache them in the new format that was introduced for release 4.51 (May
2512005). If you are upgrading from release 4.51 or later, there should be no
252problem.
253
26da7e20 254
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255Exim version 4.63
256-----------------
257
258When an SMTP error message is specified in a "message" modifier in an ACL, or
259in a :fail: or :defer: message in a redirect router, Exim now checks the start
260of the message for an SMTP error code. This consists of three digits followed
261by a space, optionally followed by an extended code of the form n.n.n, also
262followed by a space. If this is the case and the very first digit is the same
263as the default error code, the code from the message is used instead. If the
264very first digit is incorrect, a panic error is logged, and the default code is
265used. This is an incompatible change, but it is not expected to affect many (if
266any) configurations. It is possible to suppress the use of the supplied code in
267a redirect router by setting the smtp_error_code option false. In this case,
268any SMTP code is quietly ignored.
269
270
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271Exim version 4.61
272-----------------
273
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2741. The default number of ACL variables of each type has been increased to 20,
275and it's possible to compile Exim with more. You can safely upgrade to this
276release if you already have messages on the queue with saved ACL variable
277values. However, if you downgrade from this release with messages on the queue,
278any saved ACL values they may have will be lost.
279
2802. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
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281
282
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283Exim version 4.54
284-----------------
285
286There was a problem with 4.52/TF/02 in that a "name=" option on control=
287submission terminated at the next slash, thereby not allowing for slashes in
288the name. This has been changed so that "name=" takes the rest of the string as
289its data. It must therefore be the last option.
290
291
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292Version 4.53
293------------
294
295If you are using the experimental Domain Keys support, you must upgrade to
296at least libdomainkeys 0.67 in order to run this release of Exim.
297
298
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299Version 4.51
300------------
301
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3021. The format in which GnuTLS parameters are cached (in the file gnutls-params
303in the spool directory) has been changed. The new format can also be generated
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304externally, so it is now possible to update the values from outside Exim. This
305has been implemented in an upwards, BUT NOT downwards, compatible manner.
306Upgrading should be seamless: when Exim finds that it cannot understand an
307existing cache file, it generates new parameters and writes them to the cache
308in the new format. If, however, you downgrade from 4.51 to a previous release,
309you MUST delete the gnutls-params file in the spool directory, because the
310older Exim will not recognize the new format.
311
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3122. When doing a callout as part of verifying an address, Exim was not paying
313attention to any local part prefix or suffix that was matched by the router
314that accepted the address. It now behaves in the same way as it does for
315delivery: the affixes are removed from the local part unless
316rcpt_include_affixes is set on the transport. If you have a configuration that
317uses prefixes or suffixes on addresses that could be used for callouts, and you
318want the affixes to be retained, you must make sure that rcpt_include_affixes
319is set on the transport.
320
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3213. Bounce and delay warning messages no longer contain details of delivery
322errors, except for explicit messages (e.g. generated by :fail:) and SMTP
323responses from remote hosts.
324
b5aea5e1 325
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326Version 4.50
327------------
328
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329The exicyclog script has been updated to use three-digit numbers in rotated log
330files if the maximum number to keep is greater than 99. If you are already
331keeping more than 99, there will be an incompatible change when you upgrade.
332You will probably want to rename your old log files to the new form before
c3af992c 333running the new exicyclog.
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334
335
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336Version 4.42
337------------
338
339RFC 3848 specifies standard names for the "with" phrase in Received: header
340lines when AUTH and/or TLS are in use. This is the "received protocol"
341field. Exim used to use "asmtp" for authenticated SMTP, without any
342indication (in the protocol name) for TLS use. Now it follows the RFC and
343uses "esmtpa" if the connection is authenticated, "esmtps" if it is
344encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
345appear in log lines as well as in Received: header lines.
346
347
348Version 4.34
349------------
350
351Change 4.31/2 gave problems to data ACLs and local_scan() functions that
352expected to see a Received: header. I have changed to yet another scheme. The
353Received: header is now generated after the body is received, but before the
354ACL or local_scan() is called. After they have run, the timestamp in the
355Received: header is updated.
356
357Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
358which is lucky, since I decided it was a bug fix.
359
360
361Version 4.33
362------------
363
364If an expansion in a condition on a "warn" statement fails because a lookup
365defers, the "warn" statement is abandoned, and the next ACL statement is
366processed. Previously this caused the whole ACL to be aborted.
367
368
369Version 4.32
370------------
371
372Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
373verification now uses <> in the MAIL command by default, as it did before. A
374new callout option, "use_sender", has been added to request the other
375behaviour.
376
377
378Version 4.31
379------------
380
3811. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
382 or greater. The interface to the obsolete 0.8.x releases is no longer
383 supported. There is one externally visible change: the format for the
384 display of Distinguished Names now uses commas as a separator rather than a
385 slash. This is to comply with RFC 2253.
386
3872. When a message is received, the Received: header line is now generated when
388 reception is complete, instead of at the start of reception. For messages
389 that take a long time to come in, this changes the meaning of the timestamp.
390 There are several side-effects of this change:
391
392 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
393 the logged header lines no longer include the local Received: line,
394 because it has not yet been created. If the message is a non-SMTP one,
395 and the error is processed by sending a message to the sender, the copy
396 of the original message that is returned does not have an added
397 Received: line.
398
399 (b) When a filter file is tested using -bf, no additional Received: header
400 is added to the test message. After some thought, I decided that this
401 is a bug fix.
402
403 The contents of $received_for are not affected by this change. This
404 variable still contains the single recipient of a message, copied after
405 addresses have been rewritten, but before local_scan() is run.
406
4072. Recipient callout verification, like sender verification, was using <> in
408 the MAIL FROM command. This isn't really the right thing, since the actual
409 sender may affect whether the remote host accepts the recipient or not. I
410 have changed it to use the actual sender in the callout; this means that
411 the cache record is now keyed on a recipient/sender pair, not just the
412 recipient address. There doesn't seem to be a real danger of callout loops,
413 since a callout by the remote host to check the sender would use <>.
414
415
416Version 4.30
417------------
418
4191. I have abolished timeout_DNS as an error that can be detected in retry
420 rules, because it has never worked. Despite the fact that it has been
421 documented since at least release 1.62, there was no code to support it.
422 If you have used it in your retry rules, you will now get a warning message
423 to the log and panic log. It is now treated as plain "timeout".
424
4252. After discussion on the mailing list, Exim no longer adds From:, Date:, or
426 Message-Id: header lines to messages that do not originate locally, that is,
427 messages that have an associated sending host address.
428
4293. When looking up a host name from an IP address, Exim now tries the DNS
430 first, and only if that fails does it use gethostbyaddr() (or equivalent).
431 This change was made because on some OS, not all the names are given for
432 addresses with multiple PTR records via the gethostbyaddr() interface. The
433 order of lookup can be changed by setting host_lookup_order.
434
435
436Version 4.23
437------------
438
4391. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
440 that cannot be overridden. The default in the distributed EDITME is "root".
441 If for some reason you were (against advice) running deliveries as root, you
442 will have to ensure that FIXED_NEVER_USERS is not set in your
443 Local/Makefile.
444
4452. The ${quote: operator now quotes an empty string, which it did not before.
446
4473. Version 4.23 saves the contents of the ACL variables with the message, so
448 that they can be used later. If one of these variables contains a newline,
449 there will be a newline character in the spool that will not be interpreted
450 correctely by a previous version of Exim. (Exim ignores keyed spool file
451 items that it doesn't understand - precisely for this kind of problem - but
452 it expects them all to be on one line.)
453
454 So the bottom line is: if you have newlines in your ACL variables, you
455 cannot retreat from 4.23.
456
457
458Version 4.21
459------------
460
4611. The idea of the "warn" ACL verb is that it adds a header or writes to the
462 log only when "message" or "log_message" are set. However, if one of the
463 conditions was an address verification, or a call to a nested ACL, the
464 messages generated by the underlying test were being passed through. This
465 no longer happens. The underlying message is available in $acl_verify_
466 message for both "message" and "log_message" expansions, so it can be
467 passed through if needed.
468
4692. The way that the $h_ (and $header_) expansions work has been changed by the
470 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
471 until release 4.30, then the manual) for full details. Briefly, there are
472 now three forms:
473
474 $rh_xxx: and $rheader_xxx: give the original content of the header
475 line(s), with no processing at all.
476
477 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
478 then decode base64 or quoted-printable "words" within the header text,
479 but do not do charset translation.
480
481 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
482 standard character set.
483
484 If you have previously been using $h_ expansions to access the raw
485 characters, you should change to $rh_ instead.
486
4873. When Exim creates an RFC 2047 encoded word in a header line, it labels it
488 with the default character set from the headers_charset option instead of
489 always using iso-8859-1.
490
4914. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
492 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
493 called TMPDIR, and if it finds it is different, it changes its value.
494
4955. Following a discussion on the list, the rules by which Exim recognises line
496 endings on incoming messages have been changed. The -dropcr and drop_cr
497 options are now no-ops, retained only for backwards compatibility. The
498 following line terminators are recognized: LF CRLF CR. However, special
499 processing applies to CR:
500
501 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
502 nor a local message in the state where . is a terminator.
503
504 (ii) If a bare CR is encountered in a header line, an extra space is added
505 after the line terminator so as not to end the header. The reasoning
506 behind this is that bare CRs in header lines are most likely either
507 to be mistakes, or people trying to play silly games.
508
5096. The code for using daemon_smtp_port, local_interfaces, and the -oX options
510 has been reorganized. It is supposed to be backwards compatible, but it is
511 mentioned here just in case I've screwed up.
512
513
514
515Version 4.20
516------------
517
5181. I have tidied and re-organized the code that uses alarm() for imposing time
519 limits on various things. It shouldn't affect anything, but if you notice
520 processes getting stuck, it may be that I've broken something.
521
5222. The "arguments" log selector now also logs the current working directory
523 when Exim is called.
524
5253. An incompatible change has been made to the appendfile transport. This
526 affects the case when it is used for file deliveries that are set up by
527 .forward and filter files. Previously, any settings of the "file" or
528 "directory" options were ignored. It is hoped that, like the address_file
529 transport in the default configuration, these options were never in fact set
530 on such transports, because they were of no use.
531
532 Now, if either of these options is set, it is used. The path that is passed
533 by the router is in $address_file (this is not new), so it can be used as
534 part of a longer path, or modified in any other way that expansion permits.
535
536 If neither "file" nor "directory" is set, the behaviour is unchanged.
537
5384. Related to the above: in a filter, if a "save" command specifies a non-
539 absolute path, the value of $home/ is pre-pended. This no longer happens if
540 $home is unset or is set to an empty string.
541
5425. Multiple file deliveries from a filter or .forward file can never be
543 batched; the value of batch_max on the transport is ignored for file
544 deliveries. I'm assuming that nobody ever actually set batch_max on the
545 address_file transport - it would have had odd effects previously.
546
5476. DESTDIR is the more common variable that ROOT for use when installing
548 software under a different root filing system. The Exim install script now
549 recognizes DESTDIR first; if it is not set, ROOT is used.
550
5517. If DESTDIR is set when installing Exim, it no longer prepends its value to
552 the path of the system aliases file that appears in the default
553 configuration (when a default configuration is installed). If an aliases
554 file is actually created, its name *does* use the prefix.
555
556
557Version 4.14
558------------
559
5601. The default for the maximum number of unknown SMTP commands that Exim will
561accept before dropping a connection has been reduced from 5 to 3. However, you
562can now change the value by setting smtp_max_unknown_commands.
563
5642. The ${quote: operator has been changed so that it turns newline and carriage
565return characters into \n and \r, respectively.
566
5673. The file names used for maildir messages now include the microsecond time
568fraction as well as the time in seconds, to cope with systems where the process
569id can be re-used within the same second. The format is now
570
571 <time>.H<microsec>P<pid>.<host>
572
573This should be a compatible change, but is noted here just in case.
574
5754. The rules for creating message ids have changed, to cope with systems where
576the process id can be re-used within the same second. The format, however, is
577unchanged, so this should not cause any problems, except as noted in the next
578item.
579
5805. The maximum value for localhost_number has been reduced from 255 to 16, in
581order to implement the new message id rules. For operating systems that have
582case-insensitive file systems (Cygwin and Darwin), the limit is 10.
583
5846. verify = header_syntax was allowing unqualified addresses in all cases. Now
585it allows them only for locally generated messages and from hosts that match
586sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
587
5887. For reasons lost in the mists of time, when a pipe transport was run, the
589environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
590form used in Message-ID: header lines). The 'E' has been removed.
591
592
593Version 4.11
594------------
595
5961. The handling of lines in the configuration file has changed. Previously,
597macro expansion was applied to logical lines, after continuations had been
598joined on. This meant that it could not be used in .include lines, which are
599handled as physical rather than logical lines. Macro expansion is now done on
600physical lines rather than logical lines. This means there are two
601incompatibilities:
602
603 (a) A macro that expands to # to turn a line into a comment now applies only
604 to the physical line where it appears. Previously, it would have caused
605 any following continuations also to be ignored.
606
607 (b) A macro name can no longer be split over the boundary between a line and
608 its continuation. Actually, this is more of a bug fix. :-)
609
6102. The -D command line option must now all be within one command line item.
611This makes it possible to use -D to set a macro to the empty string by commands
612such as
613
614 exim -DABC ...
615 exim -DABC= ...
616
617Previously, these items would have moved on to the next item on the command
618line. To include spaces in a macro definition item, quotes must be used, in
619which case you can also have spaces after -D and surrounding the equals. For
620example:
621
622 exim '-D ABC = something' ...
623
6243. The way that addresses that redirect to themselves are handled has been
625changed, in order to fix an obscure bug. This should not cause any problems
626except in the case of wanting to go back from a 4.11 (or later) release to an
627earlier release. If there are undelivered messages on the spool that contain
628addresses which redirect to themselves, and the redirected addresses have
629already been delivered, you might get a duplicate delivery if you revert to an
630earlier Exim.
631
6324. The default way of looking up IP addresses for hosts in the manualroute and
633queryprogram routers has been changed. If "byname" or "bydns" is explicitly
634specified, there is no change, but if no method is specified, Exim now behaves
635as follows:
636
637 First, a DNS lookup is done. If this yields anything other than
638 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
639 getipnodebyname() (or gethostbyname() on older systems) and the result of the
640 lookup is the result of that call.
641
642This change has been made because it has been discovered that on some systems,
643if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
644returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
645first, and only if that gives a definite "no such host" to try the local
646function.
647
6485. In fixing the minor security problem with pid_file_path, I have removed some
649backwards-compatible (undocumented) code which was present to ease conversion
650from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
651contain "%s", which was replaced by the port number for daemons listening on
652non-standard ports. In Exim 4, such daemons do not write a pid file. The
653backwards compatibility feature was to replace "%s" by nothing if it occurred
654in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
655the problem by removing the backwards compatibility feature. Thus, if you still
656have "%s" somewhere in a setting of pid_file_path, you should remove it.
657
6586. There has been an extension to lsearch files. The keys in these files may
659now be quoted in order to allow for whitespace and colons in them. This means
660that if you were previously using keys that began with a doublequote, you will
661now have to wrap them with extra quotes and escape the internal quotes. The
662possibility that anybody is actually doing this seems extremely remote, but it
663is documented just in case.
664
665
666Version 4.10
667------------
668
669The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
670to better reflect its function. The OS-specific files have been updated. Only
671if you have explicitly set this in your Makefile (highly unlikely) do you need
672to change anything.
673
674****