OS-dependent locations for CHMOD_COMMAND, required by exicyclog (bug#602)
[exim.git] / src / README.UPDATING
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3c223874 1$Cambridge: exim/src/README.UPDATING,v 1.16 2007/06/20 14:19:23 ph10 Exp $
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2
3This document contains detailed information about incompatibilities that might
4be encountered when upgrading from one release of Exim to another. The
5information is in reverse order of release numbers. Mostly these are relatively
6small points, and the configuration file is normally upwards compatible, but
7there have been two big upheavals...
8
9
10**************************************************************************
11* There was a big reworking of the way mail routing works for release *
12* 4.00. Previously used "directors" were abolished, and all routing is *
13* now done by routers. Policy controls for incoming mail are now done by *
14* Access Control Lists instead of separate options. All this means that *
15* pre-4.00 configuration files have to be massively converted. If you *
16* are coming from a 3.xx release, please read the document in the file *
17* doc/Exim4.upgrade, and allow some time to complete the upgrade. *
18* *
19* There was a big reworking of the way domain/host/net/address lists are *
20* handled at release 3.00. If you are coming from a pre-3.00 release, it *
21* might be easier to start again from a default configuration. Otherwise *
22* you need to read doc/Exim3.upgrade and do a double conversion of your *
23* configuration file. *
24**************************************************************************
25
26
27The rest of this document contains information about changes in 4.xx releases
28that might affect a running system.
29
30
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31Exim version 4.68
32-----------------
33
341. The internal implementation of the database keys that are used for ACL
35ratelimiting has been tidied up. This means that an update to 4.68 might cause
36Exim to "forget" previous rates that it had calculated, and reset them to zero.
37
38
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39Exim version 4.64
40-----------------
41
421. Callouts were setting the name used for EHLO/HELO from $smtp_active_
43hostname. This is wrong, because it relates to the incoming message (and
44probably the interface on which it is arriving) and not to the outgoing
45callout (which could be using a different interface). This has been
46changed to use the value of the helo_data option from the smtp transport
47instead - this is what is used when a message is actually being sent. If
48there is no remote transport (possible with a router that sets up host
49addresses), $smtp_active_hostname is used. This change is mentioned here in
50case somebody is relying on the use of $smtp_active_hostname.
51
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522. A bug has been fixed that might just possibly be something that is relied on
53in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
54empty string (that is {}) was being interpreted as if it was {0} and therefore
55treated as the number zero. From release 4.64, such strings cause an error
56because a decimal number, possibly followed by K or M, is required (as has
57always been documented).
58
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593. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
60Exim's performance. Unfortunately, this has the side effect of being slightly
61non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
62one of these earlier versions and you use GnuTLS, you must remove the file
63called gnutls-params in Exim's spool directory. If you don't do this, you will
64see this error:
65
66 TLS error on connection from ... (DH params import): Base64 decoding error.
67
68Removing the file causes Exim to recompute the relevant encryption parameters
69and cache them in the new format that was introduced for release 4.51 (May
702005). If you are upgrading from release 4.51 or later, there should be no
71problem.
72
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74Exim version 4.63
75-----------------
76
77When an SMTP error message is specified in a "message" modifier in an ACL, or
78in a :fail: or :defer: message in a redirect router, Exim now checks the start
79of the message for an SMTP error code. This consists of three digits followed
80by a space, optionally followed by an extended code of the form n.n.n, also
81followed by a space. If this is the case and the very first digit is the same
82as the default error code, the code from the message is used instead. If the
83very first digit is incorrect, a panic error is logged, and the default code is
84used. This is an incompatible change, but it is not expected to affect many (if
85any) configurations. It is possible to suppress the use of the supplied code in
86a redirect router by setting the smtp_error_code option false. In this case,
87any SMTP code is quietly ignored.
88
89
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90Exim version 4.61
91-----------------
92
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931. The default number of ACL variables of each type has been increased to 20,
94and it's possible to compile Exim with more. You can safely upgrade to this
95release if you already have messages on the queue with saved ACL variable
96values. However, if you downgrade from this release with messages on the queue,
97any saved ACL values they may have will be lost.
98
992. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
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100
101
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102Exim version 4.54
103-----------------
104
105There was a problem with 4.52/TF/02 in that a "name=" option on control=
106submission terminated at the next slash, thereby not allowing for slashes in
107the name. This has been changed so that "name=" takes the rest of the string as
108its data. It must therefore be the last option.
109
110
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111Version 4.53
112------------
113
114If you are using the experimental Domain Keys support, you must upgrade to
115at least libdomainkeys 0.67 in order to run this release of Exim.
116
117
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118Version 4.51
119------------
120
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1211. The format in which GnuTLS parameters are cached (in the file gnutls-params
122in the spool directory) has been changed. The new format can also be generated
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123externally, so it is now possible to update the values from outside Exim. This
124has been implemented in an upwards, BUT NOT downwards, compatible manner.
125Upgrading should be seamless: when Exim finds that it cannot understand an
126existing cache file, it generates new parameters and writes them to the cache
127in the new format. If, however, you downgrade from 4.51 to a previous release,
128you MUST delete the gnutls-params file in the spool directory, because the
129older Exim will not recognize the new format.
130
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1312. When doing a callout as part of verifying an address, Exim was not paying
132attention to any local part prefix or suffix that was matched by the router
133that accepted the address. It now behaves in the same way as it does for
134delivery: the affixes are removed from the local part unless
135rcpt_include_affixes is set on the transport. If you have a configuration that
136uses prefixes or suffixes on addresses that could be used for callouts, and you
137want the affixes to be retained, you must make sure that rcpt_include_affixes
138is set on the transport.
139
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1403. Bounce and delay warning messages no longer contain details of delivery
141errors, except for explicit messages (e.g. generated by :fail:) and SMTP
142responses from remote hosts.
143
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145Version 4.50
146------------
147
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148The exicyclog script has been updated to use three-digit numbers in rotated log
149files if the maximum number to keep is greater than 99. If you are already
150keeping more than 99, there will be an incompatible change when you upgrade.
151You will probably want to rename your old log files to the new form before
c3af992c 152running the new exicyclog.
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153
154
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155Version 4.42
156------------
157
158RFC 3848 specifies standard names for the "with" phrase in Received: header
159lines when AUTH and/or TLS are in use. This is the "received protocol"
160field. Exim used to use "asmtp" for authenticated SMTP, without any
161indication (in the protocol name) for TLS use. Now it follows the RFC and
162uses "esmtpa" if the connection is authenticated, "esmtps" if it is
163encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
164appear in log lines as well as in Received: header lines.
165
166
167Version 4.34
168------------
169
170Change 4.31/2 gave problems to data ACLs and local_scan() functions that
171expected to see a Received: header. I have changed to yet another scheme. The
172Received: header is now generated after the body is received, but before the
173ACL or local_scan() is called. After they have run, the timestamp in the
174Received: header is updated.
175
176Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
177which is lucky, since I decided it was a bug fix.
178
179
180Version 4.33
181------------
182
183If an expansion in a condition on a "warn" statement fails because a lookup
184defers, the "warn" statement is abandoned, and the next ACL statement is
185processed. Previously this caused the whole ACL to be aborted.
186
187
188Version 4.32
189------------
190
191Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
192verification now uses <> in the MAIL command by default, as it did before. A
193new callout option, "use_sender", has been added to request the other
194behaviour.
195
196
197Version 4.31
198------------
199
2001. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
201 or greater. The interface to the obsolete 0.8.x releases is no longer
202 supported. There is one externally visible change: the format for the
203 display of Distinguished Names now uses commas as a separator rather than a
204 slash. This is to comply with RFC 2253.
205
2062. When a message is received, the Received: header line is now generated when
207 reception is complete, instead of at the start of reception. For messages
208 that take a long time to come in, this changes the meaning of the timestamp.
209 There are several side-effects of this change:
210
211 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
212 the logged header lines no longer include the local Received: line,
213 because it has not yet been created. If the message is a non-SMTP one,
214 and the error is processed by sending a message to the sender, the copy
215 of the original message that is returned does not have an added
216 Received: line.
217
218 (b) When a filter file is tested using -bf, no additional Received: header
219 is added to the test message. After some thought, I decided that this
220 is a bug fix.
221
222 The contents of $received_for are not affected by this change. This
223 variable still contains the single recipient of a message, copied after
224 addresses have been rewritten, but before local_scan() is run.
225
2262. Recipient callout verification, like sender verification, was using <> in
227 the MAIL FROM command. This isn't really the right thing, since the actual
228 sender may affect whether the remote host accepts the recipient or not. I
229 have changed it to use the actual sender in the callout; this means that
230 the cache record is now keyed on a recipient/sender pair, not just the
231 recipient address. There doesn't seem to be a real danger of callout loops,
232 since a callout by the remote host to check the sender would use <>.
233
234
235Version 4.30
236------------
237
2381. I have abolished timeout_DNS as an error that can be detected in retry
239 rules, because it has never worked. Despite the fact that it has been
240 documented since at least release 1.62, there was no code to support it.
241 If you have used it in your retry rules, you will now get a warning message
242 to the log and panic log. It is now treated as plain "timeout".
243
2442. After discussion on the mailing list, Exim no longer adds From:, Date:, or
245 Message-Id: header lines to messages that do not originate locally, that is,
246 messages that have an associated sending host address.
247
2483. When looking up a host name from an IP address, Exim now tries the DNS
249 first, and only if that fails does it use gethostbyaddr() (or equivalent).
250 This change was made because on some OS, not all the names are given for
251 addresses with multiple PTR records via the gethostbyaddr() interface. The
252 order of lookup can be changed by setting host_lookup_order.
253
254
255Version 4.23
256------------
257
2581. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
259 that cannot be overridden. The default in the distributed EDITME is "root".
260 If for some reason you were (against advice) running deliveries as root, you
261 will have to ensure that FIXED_NEVER_USERS is not set in your
262 Local/Makefile.
263
2642. The ${quote: operator now quotes an empty string, which it did not before.
265
2663. Version 4.23 saves the contents of the ACL variables with the message, so
267 that they can be used later. If one of these variables contains a newline,
268 there will be a newline character in the spool that will not be interpreted
269 correctely by a previous version of Exim. (Exim ignores keyed spool file
270 items that it doesn't understand - precisely for this kind of problem - but
271 it expects them all to be on one line.)
272
273 So the bottom line is: if you have newlines in your ACL variables, you
274 cannot retreat from 4.23.
275
276
277Version 4.21
278------------
279
2801. The idea of the "warn" ACL verb is that it adds a header or writes to the
281 log only when "message" or "log_message" are set. However, if one of the
282 conditions was an address verification, or a call to a nested ACL, the
283 messages generated by the underlying test were being passed through. This
284 no longer happens. The underlying message is available in $acl_verify_
285 message for both "message" and "log_message" expansions, so it can be
286 passed through if needed.
287
2882. The way that the $h_ (and $header_) expansions work has been changed by the
289 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
290 until release 4.30, then the manual) for full details. Briefly, there are
291 now three forms:
292
293 $rh_xxx: and $rheader_xxx: give the original content of the header
294 line(s), with no processing at all.
295
296 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
297 then decode base64 or quoted-printable "words" within the header text,
298 but do not do charset translation.
299
300 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
301 standard character set.
302
303 If you have previously been using $h_ expansions to access the raw
304 characters, you should change to $rh_ instead.
305
3063. When Exim creates an RFC 2047 encoded word in a header line, it labels it
307 with the default character set from the headers_charset option instead of
308 always using iso-8859-1.
309
3104. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
311 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
312 called TMPDIR, and if it finds it is different, it changes its value.
313
3145. Following a discussion on the list, the rules by which Exim recognises line
315 endings on incoming messages have been changed. The -dropcr and drop_cr
316 options are now no-ops, retained only for backwards compatibility. The
317 following line terminators are recognized: LF CRLF CR. However, special
318 processing applies to CR:
319
320 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
321 nor a local message in the state where . is a terminator.
322
323 (ii) If a bare CR is encountered in a header line, an extra space is added
324 after the line terminator so as not to end the header. The reasoning
325 behind this is that bare CRs in header lines are most likely either
326 to be mistakes, or people trying to play silly games.
327
3286. The code for using daemon_smtp_port, local_interfaces, and the -oX options
329 has been reorganized. It is supposed to be backwards compatible, but it is
330 mentioned here just in case I've screwed up.
331
332
333
334Version 4.20
335------------
336
3371. I have tidied and re-organized the code that uses alarm() for imposing time
338 limits on various things. It shouldn't affect anything, but if you notice
339 processes getting stuck, it may be that I've broken something.
340
3412. The "arguments" log selector now also logs the current working directory
342 when Exim is called.
343
3443. An incompatible change has been made to the appendfile transport. This
345 affects the case when it is used for file deliveries that are set up by
346 .forward and filter files. Previously, any settings of the "file" or
347 "directory" options were ignored. It is hoped that, like the address_file
348 transport in the default configuration, these options were never in fact set
349 on such transports, because they were of no use.
350
351 Now, if either of these options is set, it is used. The path that is passed
352 by the router is in $address_file (this is not new), so it can be used as
353 part of a longer path, or modified in any other way that expansion permits.
354
355 If neither "file" nor "directory" is set, the behaviour is unchanged.
356
3574. Related to the above: in a filter, if a "save" command specifies a non-
358 absolute path, the value of $home/ is pre-pended. This no longer happens if
359 $home is unset or is set to an empty string.
360
3615. Multiple file deliveries from a filter or .forward file can never be
362 batched; the value of batch_max on the transport is ignored for file
363 deliveries. I'm assuming that nobody ever actually set batch_max on the
364 address_file transport - it would have had odd effects previously.
365
3666. DESTDIR is the more common variable that ROOT for use when installing
367 software under a different root filing system. The Exim install script now
368 recognizes DESTDIR first; if it is not set, ROOT is used.
369
3707. If DESTDIR is set when installing Exim, it no longer prepends its value to
371 the path of the system aliases file that appears in the default
372 configuration (when a default configuration is installed). If an aliases
373 file is actually created, its name *does* use the prefix.
374
375
376Version 4.14
377------------
378
3791. The default for the maximum number of unknown SMTP commands that Exim will
380accept before dropping a connection has been reduced from 5 to 3. However, you
381can now change the value by setting smtp_max_unknown_commands.
382
3832. The ${quote: operator has been changed so that it turns newline and carriage
384return characters into \n and \r, respectively.
385
3863. The file names used for maildir messages now include the microsecond time
387fraction as well as the time in seconds, to cope with systems where the process
388id can be re-used within the same second. The format is now
389
390 <time>.H<microsec>P<pid>.<host>
391
392This should be a compatible change, but is noted here just in case.
393
3944. The rules for creating message ids have changed, to cope with systems where
395the process id can be re-used within the same second. The format, however, is
396unchanged, so this should not cause any problems, except as noted in the next
397item.
398
3995. The maximum value for localhost_number has been reduced from 255 to 16, in
400order to implement the new message id rules. For operating systems that have
401case-insensitive file systems (Cygwin and Darwin), the limit is 10.
402
4036. verify = header_syntax was allowing unqualified addresses in all cases. Now
404it allows them only for locally generated messages and from hosts that match
405sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
406
4077. For reasons lost in the mists of time, when a pipe transport was run, the
408environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
409form used in Message-ID: header lines). The 'E' has been removed.
410
411
412Version 4.11
413------------
414
4151. The handling of lines in the configuration file has changed. Previously,
416macro expansion was applied to logical lines, after continuations had been
417joined on. This meant that it could not be used in .include lines, which are
418handled as physical rather than logical lines. Macro expansion is now done on
419physical lines rather than logical lines. This means there are two
420incompatibilities:
421
422 (a) A macro that expands to # to turn a line into a comment now applies only
423 to the physical line where it appears. Previously, it would have caused
424 any following continuations also to be ignored.
425
426 (b) A macro name can no longer be split over the boundary between a line and
427 its continuation. Actually, this is more of a bug fix. :-)
428
4292. The -D command line option must now all be within one command line item.
430This makes it possible to use -D to set a macro to the empty string by commands
431such as
432
433 exim -DABC ...
434 exim -DABC= ...
435
436Previously, these items would have moved on to the next item on the command
437line. To include spaces in a macro definition item, quotes must be used, in
438which case you can also have spaces after -D and surrounding the equals. For
439example:
440
441 exim '-D ABC = something' ...
442
4433. The way that addresses that redirect to themselves are handled has been
444changed, in order to fix an obscure bug. This should not cause any problems
445except in the case of wanting to go back from a 4.11 (or later) release to an
446earlier release. If there are undelivered messages on the spool that contain
447addresses which redirect to themselves, and the redirected addresses have
448already been delivered, you might get a duplicate delivery if you revert to an
449earlier Exim.
450
4514. The default way of looking up IP addresses for hosts in the manualroute and
452queryprogram routers has been changed. If "byname" or "bydns" is explicitly
453specified, there is no change, but if no method is specified, Exim now behaves
454as follows:
455
456 First, a DNS lookup is done. If this yields anything other than
457 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
458 getipnodebyname() (or gethostbyname() on older systems) and the result of the
459 lookup is the result of that call.
460
461This change has been made because it has been discovered that on some systems,
462if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
463returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
464first, and only if that gives a definite "no such host" to try the local
465function.
466
4675. In fixing the minor security problem with pid_file_path, I have removed some
468backwards-compatible (undocumented) code which was present to ease conversion
469from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
470contain "%s", which was replaced by the port number for daemons listening on
471non-standard ports. In Exim 4, such daemons do not write a pid file. The
472backwards compatibility feature was to replace "%s" by nothing if it occurred
473in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
474the problem by removing the backwards compatibility feature. Thus, if you still
475have "%s" somewhere in a setting of pid_file_path, you should remove it.
476
4776. There has been an extension to lsearch files. The keys in these files may
478now be quoted in order to allow for whitespace and colons in them. This means
479that if you were previously using keys that began with a doublequote, you will
480now have to wrap them with extra quotes and escape the internal quotes. The
481possibility that anybody is actually doing this seems extremely remote, but it
482is documented just in case.
483
484
485Version 4.10
486------------
487
488The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
489to better reflect its function. The OS-specific files have been updated. Only
490if you have explicitly set this in your Makefile (highly unlikely) do you need
491to change anything.
492
493****