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[exim.git] / src / README.UPDATING
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8def5aaf 1$Cambridge: exim/src/README.UPDATING,v 1.11 2006/02/20 16:31:49 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 4.61
32-----------------
33
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341. The default number of ACL variables of each type has been increased to 20,
35and it's possible to compile Exim with more. You can safely upgrade to this
36release if you already have messages on the queue with saved ACL variable
37values. However, if you downgrade from this release with messages on the queue,
38any saved ACL values they may have will be lost.
39
402. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
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41
42
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43Exim version 4.54
44-----------------
45
46There was a problem with 4.52/TF/02 in that a "name=" option on control=
47submission terminated at the next slash, thereby not allowing for slashes in
48the name. This has been changed so that "name=" takes the rest of the string as
49its data. It must therefore be the last option.
50
51
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52Version 4.53
53------------
54
55If you are using the experimental Domain Keys support, you must upgrade to
56at least libdomainkeys 0.67 in order to run this release of Exim.
57
58
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59Version 4.51
60------------
61
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621. The format in which GnuTLS parameters are cached (in the file gnutls-params
63in the spool directory) has been changed. The new format can also be generated
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64externally, so it is now possible to update the values from outside Exim. This
65has been implemented in an upwards, BUT NOT downwards, compatible manner.
66Upgrading should be seamless: when Exim finds that it cannot understand an
67existing cache file, it generates new parameters and writes them to the cache
68in the new format. If, however, you downgrade from 4.51 to a previous release,
69you MUST delete the gnutls-params file in the spool directory, because the
70older Exim will not recognize the new format.
71
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722. When doing a callout as part of verifying an address, Exim was not paying
73attention to any local part prefix or suffix that was matched by the router
74that accepted the address. It now behaves in the same way as it does for
75delivery: the affixes are removed from the local part unless
76rcpt_include_affixes is set on the transport. If you have a configuration that
77uses prefixes or suffixes on addresses that could be used for callouts, and you
78want the affixes to be retained, you must make sure that rcpt_include_affixes
79is set on the transport.
80
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813. Bounce and delay warning messages no longer contain details of delivery
82errors, except for explicit messages (e.g. generated by :fail:) and SMTP
83responses from remote hosts.
84
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86Version 4.50
87------------
88
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89The exicyclog script has been updated to use three-digit numbers in rotated log
90files if the maximum number to keep is greater than 99. If you are already
91keeping more than 99, there will be an incompatible change when you upgrade.
92You will probably want to rename your old log files to the new form before
c3af992c 93running the new exicyclog.
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94
95
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96Version 4.42
97------------
98
99RFC 3848 specifies standard names for the "with" phrase in Received: header
100lines when AUTH and/or TLS are in use. This is the "received protocol"
101field. Exim used to use "asmtp" for authenticated SMTP, without any
102indication (in the protocol name) for TLS use. Now it follows the RFC and
103uses "esmtpa" if the connection is authenticated, "esmtps" if it is
104encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
105appear in log lines as well as in Received: header lines.
106
107
108Version 4.34
109------------
110
111Change 4.31/2 gave problems to data ACLs and local_scan() functions that
112expected to see a Received: header. I have changed to yet another scheme. The
113Received: header is now generated after the body is received, but before the
114ACL or local_scan() is called. After they have run, the timestamp in the
115Received: header is updated.
116
117Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
118which is lucky, since I decided it was a bug fix.
119
120
121Version 4.33
122------------
123
124If an expansion in a condition on a "warn" statement fails because a lookup
125defers, the "warn" statement is abandoned, and the next ACL statement is
126processed. Previously this caused the whole ACL to be aborted.
127
128
129Version 4.32
130------------
131
132Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
133verification now uses <> in the MAIL command by default, as it did before. A
134new callout option, "use_sender", has been added to request the other
135behaviour.
136
137
138Version 4.31
139------------
140
1411. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
142 or greater. The interface to the obsolete 0.8.x releases is no longer
143 supported. There is one externally visible change: the format for the
144 display of Distinguished Names now uses commas as a separator rather than a
145 slash. This is to comply with RFC 2253.
146
1472. When a message is received, the Received: header line is now generated when
148 reception is complete, instead of at the start of reception. For messages
149 that take a long time to come in, this changes the meaning of the timestamp.
150 There are several side-effects of this change:
151
152 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
153 the logged header lines no longer include the local Received: line,
154 because it has not yet been created. If the message is a non-SMTP one,
155 and the error is processed by sending a message to the sender, the copy
156 of the original message that is returned does not have an added
157 Received: line.
158
159 (b) When a filter file is tested using -bf, no additional Received: header
160 is added to the test message. After some thought, I decided that this
161 is a bug fix.
162
163 The contents of $received_for are not affected by this change. This
164 variable still contains the single recipient of a message, copied after
165 addresses have been rewritten, but before local_scan() is run.
166
1672. Recipient callout verification, like sender verification, was using <> in
168 the MAIL FROM command. This isn't really the right thing, since the actual
169 sender may affect whether the remote host accepts the recipient or not. I
170 have changed it to use the actual sender in the callout; this means that
171 the cache record is now keyed on a recipient/sender pair, not just the
172 recipient address. There doesn't seem to be a real danger of callout loops,
173 since a callout by the remote host to check the sender would use <>.
174
175
176Version 4.30
177------------
178
1791. I have abolished timeout_DNS as an error that can be detected in retry
180 rules, because it has never worked. Despite the fact that it has been
181 documented since at least release 1.62, there was no code to support it.
182 If you have used it in your retry rules, you will now get a warning message
183 to the log and panic log. It is now treated as plain "timeout".
184
1852. After discussion on the mailing list, Exim no longer adds From:, Date:, or
186 Message-Id: header lines to messages that do not originate locally, that is,
187 messages that have an associated sending host address.
188
1893. When looking up a host name from an IP address, Exim now tries the DNS
190 first, and only if that fails does it use gethostbyaddr() (or equivalent).
191 This change was made because on some OS, not all the names are given for
192 addresses with multiple PTR records via the gethostbyaddr() interface. The
193 order of lookup can be changed by setting host_lookup_order.
194
195
196Version 4.23
197------------
198
1991. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
200 that cannot be overridden. The default in the distributed EDITME is "root".
201 If for some reason you were (against advice) running deliveries as root, you
202 will have to ensure that FIXED_NEVER_USERS is not set in your
203 Local/Makefile.
204
2052. The ${quote: operator now quotes an empty string, which it did not before.
206
2073. Version 4.23 saves the contents of the ACL variables with the message, so
208 that they can be used later. If one of these variables contains a newline,
209 there will be a newline character in the spool that will not be interpreted
210 correctely by a previous version of Exim. (Exim ignores keyed spool file
211 items that it doesn't understand - precisely for this kind of problem - but
212 it expects them all to be on one line.)
213
214 So the bottom line is: if you have newlines in your ACL variables, you
215 cannot retreat from 4.23.
216
217
218Version 4.21
219------------
220
2211. The idea of the "warn" ACL verb is that it adds a header or writes to the
222 log only when "message" or "log_message" are set. However, if one of the
223 conditions was an address verification, or a call to a nested ACL, the
224 messages generated by the underlying test were being passed through. This
225 no longer happens. The underlying message is available in $acl_verify_
226 message for both "message" and "log_message" expansions, so it can be
227 passed through if needed.
228
2292. The way that the $h_ (and $header_) expansions work has been changed by the
230 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
231 until release 4.30, then the manual) for full details. Briefly, there are
232 now three forms:
233
234 $rh_xxx: and $rheader_xxx: give the original content of the header
235 line(s), with no processing at all.
236
237 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
238 then decode base64 or quoted-printable "words" within the header text,
239 but do not do charset translation.
240
241 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
242 standard character set.
243
244 If you have previously been using $h_ expansions to access the raw
245 characters, you should change to $rh_ instead.
246
2473. When Exim creates an RFC 2047 encoded word in a header line, it labels it
248 with the default character set from the headers_charset option instead of
249 always using iso-8859-1.
250
2514. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
252 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
253 called TMPDIR, and if it finds it is different, it changes its value.
254
2555. Following a discussion on the list, the rules by which Exim recognises line
256 endings on incoming messages have been changed. The -dropcr and drop_cr
257 options are now no-ops, retained only for backwards compatibility. The
258 following line terminators are recognized: LF CRLF CR. However, special
259 processing applies to CR:
260
261 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
262 nor a local message in the state where . is a terminator.
263
264 (ii) If a bare CR is encountered in a header line, an extra space is added
265 after the line terminator so as not to end the header. The reasoning
266 behind this is that bare CRs in header lines are most likely either
267 to be mistakes, or people trying to play silly games.
268
2696. The code for using daemon_smtp_port, local_interfaces, and the -oX options
270 has been reorganized. It is supposed to be backwards compatible, but it is
271 mentioned here just in case I've screwed up.
272
273
274
275Version 4.20
276------------
277
2781. I have tidied and re-organized the code that uses alarm() for imposing time
279 limits on various things. It shouldn't affect anything, but if you notice
280 processes getting stuck, it may be that I've broken something.
281
2822. The "arguments" log selector now also logs the current working directory
283 when Exim is called.
284
2853. An incompatible change has been made to the appendfile transport. This
286 affects the case when it is used for file deliveries that are set up by
287 .forward and filter files. Previously, any settings of the "file" or
288 "directory" options were ignored. It is hoped that, like the address_file
289 transport in the default configuration, these options were never in fact set
290 on such transports, because they were of no use.
291
292 Now, if either of these options is set, it is used. The path that is passed
293 by the router is in $address_file (this is not new), so it can be used as
294 part of a longer path, or modified in any other way that expansion permits.
295
296 If neither "file" nor "directory" is set, the behaviour is unchanged.
297
2984. Related to the above: in a filter, if a "save" command specifies a non-
299 absolute path, the value of $home/ is pre-pended. This no longer happens if
300 $home is unset or is set to an empty string.
301
3025. Multiple file deliveries from a filter or .forward file can never be
303 batched; the value of batch_max on the transport is ignored for file
304 deliveries. I'm assuming that nobody ever actually set batch_max on the
305 address_file transport - it would have had odd effects previously.
306
3076. DESTDIR is the more common variable that ROOT for use when installing
308 software under a different root filing system. The Exim install script now
309 recognizes DESTDIR first; if it is not set, ROOT is used.
310
3117. If DESTDIR is set when installing Exim, it no longer prepends its value to
312 the path of the system aliases file that appears in the default
313 configuration (when a default configuration is installed). If an aliases
314 file is actually created, its name *does* use the prefix.
315
316
317Version 4.14
318------------
319
3201. The default for the maximum number of unknown SMTP commands that Exim will
321accept before dropping a connection has been reduced from 5 to 3. However, you
322can now change the value by setting smtp_max_unknown_commands.
323
3242. The ${quote: operator has been changed so that it turns newline and carriage
325return characters into \n and \r, respectively.
326
3273. The file names used for maildir messages now include the microsecond time
328fraction as well as the time in seconds, to cope with systems where the process
329id can be re-used within the same second. The format is now
330
331 <time>.H<microsec>P<pid>.<host>
332
333This should be a compatible change, but is noted here just in case.
334
3354. The rules for creating message ids have changed, to cope with systems where
336the process id can be re-used within the same second. The format, however, is
337unchanged, so this should not cause any problems, except as noted in the next
338item.
339
3405. The maximum value for localhost_number has been reduced from 255 to 16, in
341order to implement the new message id rules. For operating systems that have
342case-insensitive file systems (Cygwin and Darwin), the limit is 10.
343
3446. verify = header_syntax was allowing unqualified addresses in all cases. Now
345it allows them only for locally generated messages and from hosts that match
346sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
347
3487. For reasons lost in the mists of time, when a pipe transport was run, the
349environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
350form used in Message-ID: header lines). The 'E' has been removed.
351
352
353Version 4.11
354------------
355
3561. The handling of lines in the configuration file has changed. Previously,
357macro expansion was applied to logical lines, after continuations had been
358joined on. This meant that it could not be used in .include lines, which are
359handled as physical rather than logical lines. Macro expansion is now done on
360physical lines rather than logical lines. This means there are two
361incompatibilities:
362
363 (a) A macro that expands to # to turn a line into a comment now applies only
364 to the physical line where it appears. Previously, it would have caused
365 any following continuations also to be ignored.
366
367 (b) A macro name can no longer be split over the boundary between a line and
368 its continuation. Actually, this is more of a bug fix. :-)
369
3702. The -D command line option must now all be within one command line item.
371This makes it possible to use -D to set a macro to the empty string by commands
372such as
373
374 exim -DABC ...
375 exim -DABC= ...
376
377Previously, these items would have moved on to the next item on the command
378line. To include spaces in a macro definition item, quotes must be used, in
379which case you can also have spaces after -D and surrounding the equals. For
380example:
381
382 exim '-D ABC = something' ...
383
3843. The way that addresses that redirect to themselves are handled has been
385changed, in order to fix an obscure bug. This should not cause any problems
386except in the case of wanting to go back from a 4.11 (or later) release to an
387earlier release. If there are undelivered messages on the spool that contain
388addresses which redirect to themselves, and the redirected addresses have
389already been delivered, you might get a duplicate delivery if you revert to an
390earlier Exim.
391
3924. The default way of looking up IP addresses for hosts in the manualroute and
393queryprogram routers has been changed. If "byname" or "bydns" is explicitly
394specified, there is no change, but if no method is specified, Exim now behaves
395as follows:
396
397 First, a DNS lookup is done. If this yields anything other than
398 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
399 getipnodebyname() (or gethostbyname() on older systems) and the result of the
400 lookup is the result of that call.
401
402This change has been made because it has been discovered that on some systems,
403if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
404returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
405first, and only if that gives a definite "no such host" to try the local
406function.
407
4085. In fixing the minor security problem with pid_file_path, I have removed some
409backwards-compatible (undocumented) code which was present to ease conversion
410from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
411contain "%s", which was replaced by the port number for daemons listening on
412non-standard ports. In Exim 4, such daemons do not write a pid file. The
413backwards compatibility feature was to replace "%s" by nothing if it occurred
414in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
415the problem by removing the backwards compatibility feature. Thus, if you still
416have "%s" somewhere in a setting of pid_file_path, you should remove it.
417
4186. There has been an extension to lsearch files. The keys in these files may
419now be quoted in order to allow for whitespace and colons in them. This means
420that if you were previously using keys that began with a doublequote, you will
421now have to wrap them with extra quotes and escape the internal quotes. The
422possibility that anybody is actually doing this seems extremely remote, but it
423is documented just in case.
424
425
426Version 4.10
427------------
428
429The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
430to better reflect its function. The OS-specific files have been updated. Only
431if you have explicitly set this in your Makefile (highly unlikely) do you need
432to change anything.
433
434****