1 $Cambridge: exim/src/README.UPDATING,v 1.10 2005/12/12 15:58:53 ph10 Exp $
3 This document contains detailed information about incompatibilities that might
4 be encountered when upgrading from one release of Exim to another. The
5 information is in reverse order of release numbers. Mostly these are relatively
6 small points, and the configuration file is normally upwards compatible, but
7 there have been two big upheavals...
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. *
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 **************************************************************************
27 The rest of this document contains information about changes in 4.xx releases
28 that might affect a running system.
34 The default number of ACL variables of each type has been increased to 20, and
35 it's possible to compile Exim with more. You can safely upgrade to this release
36 if you already have messages on the queue with saved ACL variable values.
37 However, if you downgrade from this release with messages on the queue, any
38 saved ACL values they may have will be lost.
44 There was a problem with 4.52/TF/02 in that a "name=" option on control=
45 submission terminated at the next slash, thereby not allowing for slashes in
46 the name. This has been changed so that "name=" takes the rest of the string as
47 its data. It must therefore be the last option.
53 If you are using the experimental Domain Keys support, you must upgrade to
54 at least libdomainkeys 0.67 in order to run this release of Exim.
60 1. The format in which GnuTLS parameters are cached (in the file gnutls-params
61 in the spool directory) has been changed. The new format can also be generated
62 externally, so it is now possible to update the values from outside Exim. This
63 has been implemented in an upwards, BUT NOT downwards, compatible manner.
64 Upgrading should be seamless: when Exim finds that it cannot understand an
65 existing cache file, it generates new parameters and writes them to the cache
66 in the new format. If, however, you downgrade from 4.51 to a previous release,
67 you MUST delete the gnutls-params file in the spool directory, because the
68 older Exim will not recognize the new format.
70 2. When doing a callout as part of verifying an address, Exim was not paying
71 attention to any local part prefix or suffix that was matched by the router
72 that accepted the address. It now behaves in the same way as it does for
73 delivery: the affixes are removed from the local part unless
74 rcpt_include_affixes is set on the transport. If you have a configuration that
75 uses prefixes or suffixes on addresses that could be used for callouts, and you
76 want the affixes to be retained, you must make sure that rcpt_include_affixes
77 is set on the transport.
79 3. Bounce and delay warning messages no longer contain details of delivery
80 errors, except for explicit messages (e.g. generated by :fail:) and SMTP
81 responses from remote hosts.
87 The exicyclog script has been updated to use three-digit numbers in rotated log
88 files if the maximum number to keep is greater than 99. If you are already
89 keeping more than 99, there will be an incompatible change when you upgrade.
90 You will probably want to rename your old log files to the new form before
91 running the new exicyclog.
97 RFC 3848 specifies standard names for the "with" phrase in Received: header
98 lines when AUTH and/or TLS are in use. This is the "received protocol"
99 field. Exim used to use "asmtp" for authenticated SMTP, without any
100 indication (in the protocol name) for TLS use. Now it follows the RFC and
101 uses "esmtpa" if the connection is authenticated, "esmtps" if it is
102 encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
103 appear in log lines as well as in Received: header lines.
109 Change 4.31/2 gave problems to data ACLs and local_scan() functions that
110 expected to see a Received: header. I have changed to yet another scheme. The
111 Received: header is now generated after the body is received, but before the
112 ACL or local_scan() is called. After they have run, the timestamp in the
113 Received: header is updated.
115 Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
116 which is lucky, since I decided it was a bug fix.
122 If an expansion in a condition on a "warn" statement fails because a lookup
123 defers, the "warn" statement is abandoned, and the next ACL statement is
124 processed. Previously this caused the whole ACL to be aborted.
130 Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
131 verification now uses <> in the MAIL command by default, as it did before. A
132 new callout option, "use_sender", has been added to request the other
139 1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
140 or greater. The interface to the obsolete 0.8.x releases is no longer
141 supported. There is one externally visible change: the format for the
142 display of Distinguished Names now uses commas as a separator rather than a
143 slash. This is to comply with RFC 2253.
145 2. When a message is received, the Received: header line is now generated when
146 reception is complete, instead of at the start of reception. For messages
147 that take a long time to come in, this changes the meaning of the timestamp.
148 There are several side-effects of this change:
150 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
151 the logged header lines no longer include the local Received: line,
152 because it has not yet been created. If the message is a non-SMTP one,
153 and the error is processed by sending a message to the sender, the copy
154 of the original message that is returned does not have an added
157 (b) When a filter file is tested using -bf, no additional Received: header
158 is added to the test message. After some thought, I decided that this
161 The contents of $received_for are not affected by this change. This
162 variable still contains the single recipient of a message, copied after
163 addresses have been rewritten, but before local_scan() is run.
165 2. Recipient callout verification, like sender verification, was using <> in
166 the MAIL FROM command. This isn't really the right thing, since the actual
167 sender may affect whether the remote host accepts the recipient or not. I
168 have changed it to use the actual sender in the callout; this means that
169 the cache record is now keyed on a recipient/sender pair, not just the
170 recipient address. There doesn't seem to be a real danger of callout loops,
171 since a callout by the remote host to check the sender would use <>.
177 1. I have abolished timeout_DNS as an error that can be detected in retry
178 rules, because it has never worked. Despite the fact that it has been
179 documented since at least release 1.62, there was no code to support it.
180 If you have used it in your retry rules, you will now get a warning message
181 to the log and panic log. It is now treated as plain "timeout".
183 2. After discussion on the mailing list, Exim no longer adds From:, Date:, or
184 Message-Id: header lines to messages that do not originate locally, that is,
185 messages that have an associated sending host address.
187 3. When looking up a host name from an IP address, Exim now tries the DNS
188 first, and only if that fails does it use gethostbyaddr() (or equivalent).
189 This change was made because on some OS, not all the names are given for
190 addresses with multiple PTR records via the gethostbyaddr() interface. The
191 order of lookup can be changed by setting host_lookup_order.
197 1. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
198 that cannot be overridden. The default in the distributed EDITME is "root".
199 If for some reason you were (against advice) running deliveries as root, you
200 will have to ensure that FIXED_NEVER_USERS is not set in your
203 2. The ${quote: operator now quotes an empty string, which it did not before.
205 3. Version 4.23 saves the contents of the ACL variables with the message, so
206 that they can be used later. If one of these variables contains a newline,
207 there will be a newline character in the spool that will not be interpreted
208 correctely by a previous version of Exim. (Exim ignores keyed spool file
209 items that it doesn't understand - precisely for this kind of problem - but
210 it expects them all to be on one line.)
212 So the bottom line is: if you have newlines in your ACL variables, you
213 cannot retreat from 4.23.
219 1. The idea of the "warn" ACL verb is that it adds a header or writes to the
220 log only when "message" or "log_message" are set. However, if one of the
221 conditions was an address verification, or a call to a nested ACL, the
222 messages generated by the underlying test were being passed through. This
223 no longer happens. The underlying message is available in $acl_verify_
224 message for both "message" and "log_message" expansions, so it can be
225 passed through if needed.
227 2. The way that the $h_ (and $header_) expansions work has been changed by the
228 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
229 until release 4.30, then the manual) for full details. Briefly, there are
232 $rh_xxx: and $rheader_xxx: give the original content of the header
233 line(s), with no processing at all.
235 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
236 then decode base64 or quoted-printable "words" within the header text,
237 but do not do charset translation.
239 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
240 standard character set.
242 If you have previously been using $h_ expansions to access the raw
243 characters, you should change to $rh_ instead.
245 3. When Exim creates an RFC 2047 encoded word in a header line, it labels it
246 with the default character set from the headers_charset option instead of
247 always using iso-8859-1.
249 4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
250 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
251 called TMPDIR, and if it finds it is different, it changes its value.
253 5. Following a discussion on the list, the rules by which Exim recognises line
254 endings on incoming messages have been changed. The -dropcr and drop_cr
255 options are now no-ops, retained only for backwards compatibility. The
256 following line terminators are recognized: LF CRLF CR. However, special
257 processing applies to CR:
259 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
260 nor a local message in the state where . is a terminator.
262 (ii) If a bare CR is encountered in a header line, an extra space is added
263 after the line terminator so as not to end the header. The reasoning
264 behind this is that bare CRs in header lines are most likely either
265 to be mistakes, or people trying to play silly games.
267 6. The code for using daemon_smtp_port, local_interfaces, and the -oX options
268 has been reorganized. It is supposed to be backwards compatible, but it is
269 mentioned here just in case I've screwed up.
276 1. I have tidied and re-organized the code that uses alarm() for imposing time
277 limits on various things. It shouldn't affect anything, but if you notice
278 processes getting stuck, it may be that I've broken something.
280 2. The "arguments" log selector now also logs the current working directory
283 3. An incompatible change has been made to the appendfile transport. This
284 affects the case when it is used for file deliveries that are set up by
285 .forward and filter files. Previously, any settings of the "file" or
286 "directory" options were ignored. It is hoped that, like the address_file
287 transport in the default configuration, these options were never in fact set
288 on such transports, because they were of no use.
290 Now, if either of these options is set, it is used. The path that is passed
291 by the router is in $address_file (this is not new), so it can be used as
292 part of a longer path, or modified in any other way that expansion permits.
294 If neither "file" nor "directory" is set, the behaviour is unchanged.
296 4. Related to the above: in a filter, if a "save" command specifies a non-
297 absolute path, the value of $home/ is pre-pended. This no longer happens if
298 $home is unset or is set to an empty string.
300 5. Multiple file deliveries from a filter or .forward file can never be
301 batched; the value of batch_max on the transport is ignored for file
302 deliveries. I'm assuming that nobody ever actually set batch_max on the
303 address_file transport - it would have had odd effects previously.
305 6. DESTDIR is the more common variable that ROOT for use when installing
306 software under a different root filing system. The Exim install script now
307 recognizes DESTDIR first; if it is not set, ROOT is used.
309 7. If DESTDIR is set when installing Exim, it no longer prepends its value to
310 the path of the system aliases file that appears in the default
311 configuration (when a default configuration is installed). If an aliases
312 file is actually created, its name *does* use the prefix.
318 1. The default for the maximum number of unknown SMTP commands that Exim will
319 accept before dropping a connection has been reduced from 5 to 3. However, you
320 can now change the value by setting smtp_max_unknown_commands.
322 2. The ${quote: operator has been changed so that it turns newline and carriage
323 return characters into \n and \r, respectively.
325 3. The file names used for maildir messages now include the microsecond time
326 fraction as well as the time in seconds, to cope with systems where the process
327 id can be re-used within the same second. The format is now
329 <time>.H<microsec>P<pid>.<host>
331 This should be a compatible change, but is noted here just in case.
333 4. The rules for creating message ids have changed, to cope with systems where
334 the process id can be re-used within the same second. The format, however, is
335 unchanged, so this should not cause any problems, except as noted in the next
338 5. The maximum value for localhost_number has been reduced from 255 to 16, in
339 order to implement the new message id rules. For operating systems that have
340 case-insensitive file systems (Cygwin and Darwin), the limit is 10.
342 6. verify = header_syntax was allowing unqualified addresses in all cases. Now
343 it allows them only for locally generated messages and from hosts that match
344 sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
346 7. For reasons lost in the mists of time, when a pipe transport was run, the
347 environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
348 form used in Message-ID: header lines). The 'E' has been removed.
354 1. The handling of lines in the configuration file has changed. Previously,
355 macro expansion was applied to logical lines, after continuations had been
356 joined on. This meant that it could not be used in .include lines, which are
357 handled as physical rather than logical lines. Macro expansion is now done on
358 physical lines rather than logical lines. This means there are two
361 (a) A macro that expands to # to turn a line into a comment now applies only
362 to the physical line where it appears. Previously, it would have caused
363 any following continuations also to be ignored.
365 (b) A macro name can no longer be split over the boundary between a line and
366 its continuation. Actually, this is more of a bug fix. :-)
368 2. The -D command line option must now all be within one command line item.
369 This makes it possible to use -D to set a macro to the empty string by commands
375 Previously, these items would have moved on to the next item on the command
376 line. To include spaces in a macro definition item, quotes must be used, in
377 which case you can also have spaces after -D and surrounding the equals. For
380 exim '-D ABC = something' ...
382 3. The way that addresses that redirect to themselves are handled has been
383 changed, in order to fix an obscure bug. This should not cause any problems
384 except in the case of wanting to go back from a 4.11 (or later) release to an
385 earlier release. If there are undelivered messages on the spool that contain
386 addresses which redirect to themselves, and the redirected addresses have
387 already been delivered, you might get a duplicate delivery if you revert to an
390 4. The default way of looking up IP addresses for hosts in the manualroute and
391 queryprogram routers has been changed. If "byname" or "bydns" is explicitly
392 specified, there is no change, but if no method is specified, Exim now behaves
395 First, a DNS lookup is done. If this yields anything other than
396 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
397 getipnodebyname() (or gethostbyname() on older systems) and the result of the
398 lookup is the result of that call.
400 This change has been made because it has been discovered that on some systems,
401 if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
402 returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
403 first, and only if that gives a definite "no such host" to try the local
406 5. In fixing the minor security problem with pid_file_path, I have removed some
407 backwards-compatible (undocumented) code which was present to ease conversion
408 from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
409 contain "%s", which was replaced by the port number for daemons listening on
410 non-standard ports. In Exim 4, such daemons do not write a pid file. The
411 backwards compatibility feature was to replace "%s" by nothing if it occurred
412 in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
413 the problem by removing the backwards compatibility feature. Thus, if you still
414 have "%s" somewhere in a setting of pid_file_path, you should remove it.
416 6. There has been an extension to lsearch files. The keys in these files may
417 now be quoted in order to allow for whitespace and colons in them. This means
418 that if you were previously using keys that began with a doublequote, you will
419 now have to wrap them with extra quotes and escape the internal quotes. The
420 possibility that anybody is actually doing this seems extremely remote, but it
421 is documented just in case.
427 The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
428 to better reflect its function. The OS-specific files have been updated. Only
429 if you have explicitly set this in your Makefile (highly unlikely) do you need
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