Merge branch 'experimental_ocsp'
[exim.git] / src / README.UPDATING
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...
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. *
25The rest of this document contains information about changes in 4.xx releases
26that might affect a running system.
2eda48c6 27
e6acf885 28
29Exim version 4.78
32 * The value of $tls_peerdn is now print-escaped when written to the spool file
33 in a -tls_peerdn line, and unescaped when read back in. We received reports
34 of values with embedded newlines, which caused spool file corruption.
36 If you have a corrupt spool file and you wish to recover the contents after
37 upgrading, then lock the message, replace the new-lines that should be part
38 of the -tls_peerdn line with the two-character sequence \n and then unlock
39 the message. No tool has been provided as we believe this is a rare
40 occurence.
42 * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built
43 against 1.0.1a then you will get a warning message and the
44 "openssl_options" value will not parse "no_tlsv1_1": the value changes
45 incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a
46 is infelicitous. We advise avoiding 1.0.1a.
48 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
50 COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
51 "+dont_insert_empty_fragments". We default to unset. That old default was
52 grandfathered in from before openssl_options became a configuration option.
53 Empty fragments are inserted by default through TLS1.0, to partially defend
54 against certain attacks; TLS1.1+ change the protocol so that this is not
55 needed. The DIEF SSL option was required for some old releases of mail
56 clients which did not gracefully handle the empty fragments, and was
57 initially set in Exim release 4.31 (see ChangeLog, item 37).
59 If you still have affected mail-clients, and you see SSL protocol failures
60 with this release of Exim, set:
61 openssl_options = +dont_insert_empty_fragments
62 in the main section of your Exim configuration file. You're trading off
63 security for compatibility. Exim is now defaulting to higher security and
64 rewarding more modern clients.
66 * Ldap lookups returning multi-valued attributes now separate the attributes
67 with only a comma, not a comma-space sequence. Also, an actual comma within
68 a returned attribute is doubled. This makes it possible to parse the
69 attribute as a comma-separated list. Note the distinction from multiple
70 attributes being returned, where each one is a name=value pair.
c80c5570 71
72 * accept_8bitmime now defaults on, which is not RFC compliant but is better
73 suited to today's Internet. See for a
74 sane rationale. Those who wish to be strictly RFC compliant, or know that
75 they need to talk to servers that are not 8-bit-clean, now need to take
76 explicit configuration action to default this option off. This is not a
77 new option, you can safely force it off before upgrading, to decouple
78 configuration changes from the binary upgrade while remaining RFC compliant.
80 * The GnuTLS support has been mostly rewritten, to use 2.12.x APIs. As part
81 of this, these three options are no longer supported:
83 gnutls_require_kx
84 gnutls_require_mac
85 gnutls_require_protocols
87 Their functionality is entirely subsumed into tls_require_ciphers, which is
88 no longer parsed apart by Exim but is instead given to
89 gnutls_priority_init(3), which is no longer an Exim list. See:
93 for fuller documentation of the strings parsed. The three gnutls_require_*
94 options are still parsed by Exim and, for this release, silently ignored.
95 A future release will add warnings, before a later still release removes
96 parsing entirely and the presence of the options will be a configuration
97 error.
99 This rewrite means that Exim will continue to build against GnuTLS in the
100 future, brings Exim closer to other GnuTLS applications and lets us add
101 support for SNI and other features more readily. We regret that it wasn't
102 feasible to retain the three dropped options.
dec5017e 104
105Exim version 4.77
108 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
109 if supported by your GnuTLS library. Use the existing
110 "gnutls_require_protocols" option to downgrade this if that will be a
111 problem. Prior to this release, supported values were "TLS1" and "SSL3",
112 so you should be able to update configuration prior to update.
114 * The match_<type>{string1}{string2} expansion conditions no longer subject
115 string2 to string expansion, unless Exim was built with the new
116 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
117 insecure configurations that way. If you need the functionality and turn on
118 that build option, please let the developers know, and know why, so we can
119 try to provide a safer mechanism for you.
121 The match{}{} expansion condition (for regular expressions) is NOT affected.
122 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
123 change is that a '$' appearing in s2 will not trigger expansion, but instead
124 will be treated as a literal $ sign; the effect is very similar to having
125 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
126 uses $expansions then those _will_ be processed as normal. It is only the
127 point at which s2 is read where expansion is inhibited.
129 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
130 If you are testing if the address in s1 occurs in the list of items given
131 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
132 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
c566dd90 134
135Exim version 4.74
138 * The integrated support for dynamically loadable lookup modules has an ABI
139 change from the modules supported by some OS vendors through an unofficial
140 patch. Don't try to mix & match.
142 * Some parts of the build system are now beginning to assume that the host
143 environment is POSIX. If you're building on a system where POSIX tools are
144 not the default, you might have an easier time if you switch to the POSIX
145 tools. Feel free to report non-POSIX issues as a request for a feature
146 enhancement, but if the POSIX variants are available then the fix will
147 probably just involve some coercion. See the README instructions for
148 building on such hosts.
151Exim version 4.73
154 * The Exim run-time user can no longer be root; this was always
155 strongly discouraged, but is now prohibited both at build and
156 run-time. If you need Exim to run routinely as root, you'll need to
157 patch the source and accept the risk. Here be dragons.
159 * Exim will no longer accept a configuration file owned by the Exim
160 run-time user, unless that account is explicitly the value in
161 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
a7ee5955 162 files are not writeable by other accounts.
164 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
165 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
166 Two new build options mitigate this.
168 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
169 files that are trusted to be selected by the Exim user; one per line.
170 This is the recommended approach going forward.
172 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
173 the Exim run-time user may safely pass without dropping privileges.
174 Because changes to this involve a recompile, this is not the recommended
175 approach but may ease transition. The values of the macros, when
43236f35 176 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
178 * The system_filter_user option now defaults to the Exim run-time user,
179 rather than root. You can still set it explicitly to root and this
180 can be done with prior versions too, letting you roll versions
181 without needing to change this configuration option.
183 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
184 defined at build time.
187Exim version 4.70
1901. Experimental Yahoo! Domainkeys support has been dropped in this release.
191It has been superceded by a native implementation of its successor DKIM.
1932. Up to version 4.69, Exim came with an embedded version of the PCRE library.
194As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
a7ee5955 195installed. Most OS distributions have ready-made library and development
2eda48c6 196packages.
199Exim version 4.68
2021. The internal implementation of the database keys that are used for ACL
203ratelimiting has been tidied up. This means that an update to 4.68 might cause
204Exim to "forget" previous rates that it had calculated, and reset them to zero.
207Exim version 4.64
2101. Callouts were setting the name used for EHLO/HELO from $smtp_active_
211hostname. This is wrong, because it relates to the incoming message (and
212probably the interface on which it is arriving) and not to the outgoing
213callout (which could be using a different interface). This has been
214changed to use the value of the helo_data option from the smtp transport
215instead - this is what is used when a message is actually being sent. If
216there is no remote transport (possible with a router that sets up host
217addresses), $smtp_active_hostname is used. This change is mentioned here in
218case somebody is relying on the use of $smtp_active_hostname.
2202. A bug has been fixed that might just possibly be something that is relied on
221in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
222empty string (that is {}) was being interpreted as if it was {0} and therefore
223treated as the number zero. From release 4.64, such strings cause an error
224because a decimal number, possibly followed by K or M, is required (as has
225always been documented).
2273. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
228Exim's performance. Unfortunately, this has the side effect of being slightly
229non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
230one of these earlier versions and you use GnuTLS, you must remove the file
231called gnutls-params in Exim's spool directory. If you don't do this, you will
232see this error:
234 TLS error on connection from ... (DH params import): Base64 decoding error.
236Removing the file causes Exim to recompute the relevant encryption parameters
237and cache them in the new format that was introduced for release 4.51 (May
2382005). If you are upgrading from release 4.51 or later, there should be no
26da7e20 241
242Exim version 4.63
245When an SMTP error message is specified in a "message" modifier in an ACL, or
246in a :fail: or :defer: message in a redirect router, Exim now checks the start
247of the message for an SMTP error code. This consists of three digits followed
248by a space, optionally followed by an extended code of the form n.n.n, also
249followed by a space. If this is the case and the very first digit is the same
250as the default error code, the code from the message is used instead. If the
251very first digit is incorrect, a panic error is logged, and the default code is
252used. This is an incompatible change, but it is not expected to affect many (if
253any) configurations. It is possible to suppress the use of the supplied code in
254a redirect router by setting the smtp_error_code option false. In this case,
255any SMTP code is quietly ignored.
258Exim version 4.61
2611. The default number of ACL variables of each type has been increased to 20,
262and it's possible to compile Exim with more. You can safely upgrade to this
263release if you already have messages on the queue with saved ACL variable
264values. However, if you downgrade from this release with messages on the queue,
265any saved ACL values they may have will be lost.
2672. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
270Exim version 4.54
273There was a problem with 4.52/TF/02 in that a "name=" option on control=
274submission terminated at the next slash, thereby not allowing for slashes in
275the name. This has been changed so that "name=" takes the rest of the string as
276its data. It must therefore be the last option.
279Version 4.53
282If you are using the experimental Domain Keys support, you must upgrade to
283at least libdomainkeys 0.67 in order to run this release of Exim.
286Version 4.51
2891. The format in which GnuTLS parameters are cached (in the file gnutls-params
290in the spool directory) has been changed. The new format can also be generated
291externally, so it is now possible to update the values from outside Exim. This
292has been implemented in an upwards, BUT NOT downwards, compatible manner.
293Upgrading should be seamless: when Exim finds that it cannot understand an
294existing cache file, it generates new parameters and writes them to the cache
295in the new format. If, however, you downgrade from 4.51 to a previous release,
296you MUST delete the gnutls-params file in the spool directory, because the
297older Exim will not recognize the new format.
2992. When doing a callout as part of verifying an address, Exim was not paying
300attention to any local part prefix or suffix that was matched by the router
301that accepted the address. It now behaves in the same way as it does for
302delivery: the affixes are removed from the local part unless
303rcpt_include_affixes is set on the transport. If you have a configuration that
304uses prefixes or suffixes on addresses that could be used for callouts, and you
305want the affixes to be retained, you must make sure that rcpt_include_affixes
306is set on the transport.
3083. Bounce and delay warning messages no longer contain details of delivery
309errors, except for explicit messages (e.g. generated by :fail:) and SMTP
310responses from remote hosts.
b5aea5e1 312
313Version 4.50
316The exicyclog script has been updated to use three-digit numbers in rotated log
317files if the maximum number to keep is greater than 99. If you are already
318keeping more than 99, there will be an incompatible change when you upgrade.
319You will probably want to rename your old log files to the new form before
c3af992c 320running the new exicyclog.
323Version 4.42
326RFC 3848 specifies standard names for the "with" phrase in Received: header
327lines when AUTH and/or TLS are in use. This is the "received protocol"
328field. Exim used to use "asmtp" for authenticated SMTP, without any
329indication (in the protocol name) for TLS use. Now it follows the RFC and
330uses "esmtpa" if the connection is authenticated, "esmtps" if it is
331encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
332appear in log lines as well as in Received: header lines.
335Version 4.34
338Change 4.31/2 gave problems to data ACLs and local_scan() functions that
339expected to see a Received: header. I have changed to yet another scheme. The
340Received: header is now generated after the body is received, but before the
341ACL or local_scan() is called. After they have run, the timestamp in the
342Received: header is updated.
344Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
345which is lucky, since I decided it was a bug fix.
348Version 4.33
351If an expansion in a condition on a "warn" statement fails because a lookup
352defers, the "warn" statement is abandoned, and the next ACL statement is
353processed. Previously this caused the whole ACL to be aborted.
356Version 4.32
359Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
360verification now uses <> in the MAIL command by default, as it did before. A
361new callout option, "use_sender", has been added to request the other
365Version 4.31
3681. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
369 or greater. The interface to the obsolete 0.8.x releases is no longer
370 supported. There is one externally visible change: the format for the
371 display of Distinguished Names now uses commas as a separator rather than a
372 slash. This is to comply with RFC 2253.
3742. When a message is received, the Received: header line is now generated when
375 reception is complete, instead of at the start of reception. For messages
376 that take a long time to come in, this changes the meaning of the timestamp.
377 There are several side-effects of this change:
379 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
380 the logged header lines no longer include the local Received: line,
381 because it has not yet been created. If the message is a non-SMTP one,
382 and the error is processed by sending a message to the sender, the copy
383 of the original message that is returned does not have an added
384 Received: line.
386 (b) When a filter file is tested using -bf, no additional Received: header
387 is added to the test message. After some thought, I decided that this
388 is a bug fix.
390 The contents of $received_for are not affected by this change. This
391 variable still contains the single recipient of a message, copied after
392 addresses have been rewritten, but before local_scan() is run.
3942. Recipient callout verification, like sender verification, was using <> in
395 the MAIL FROM command. This isn't really the right thing, since the actual
396 sender may affect whether the remote host accepts the recipient or not. I
397 have changed it to use the actual sender in the callout; this means that
398 the cache record is now keyed on a recipient/sender pair, not just the
399 recipient address. There doesn't seem to be a real danger of callout loops,
400 since a callout by the remote host to check the sender would use <>.
403Version 4.30
4061. I have abolished timeout_DNS as an error that can be detected in retry
407 rules, because it has never worked. Despite the fact that it has been
408 documented since at least release 1.62, there was no code to support it.
409 If you have used it in your retry rules, you will now get a warning message
410 to the log and panic log. It is now treated as plain "timeout".
4122. After discussion on the mailing list, Exim no longer adds From:, Date:, or
413 Message-Id: header lines to messages that do not originate locally, that is,
414 messages that have an associated sending host address.
4163. When looking up a host name from an IP address, Exim now tries the DNS
417 first, and only if that fails does it use gethostbyaddr() (or equivalent).
418 This change was made because on some OS, not all the names are given for
419 addresses with multiple PTR records via the gethostbyaddr() interface. The
420 order of lookup can be changed by setting host_lookup_order.
423Version 4.23
4261. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
427 that cannot be overridden. The default in the distributed EDITME is "root".
428 If for some reason you were (against advice) running deliveries as root, you
429 will have to ensure that FIXED_NEVER_USERS is not set in your
430 Local/Makefile.
4322. The ${quote: operator now quotes an empty string, which it did not before.
4343. Version 4.23 saves the contents of the ACL variables with the message, so
435 that they can be used later. If one of these variables contains a newline,
436 there will be a newline character in the spool that will not be interpreted
437 correctely by a previous version of Exim. (Exim ignores keyed spool file
438 items that it doesn't understand - precisely for this kind of problem - but
439 it expects them all to be on one line.)
441 So the bottom line is: if you have newlines in your ACL variables, you
442 cannot retreat from 4.23.
445Version 4.21
4481. The idea of the "warn" ACL verb is that it adds a header or writes to the
449 log only when "message" or "log_message" are set. However, if one of the
450 conditions was an address verification, or a call to a nested ACL, the
451 messages generated by the underlying test were being passed through. This
452 no longer happens. The underlying message is available in $acl_verify_
453 message for both "message" and "log_message" expansions, so it can be
454 passed through if needed.
4562. The way that the $h_ (and $header_) expansions work has been changed by the
457 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
458 until release 4.30, then the manual) for full details. Briefly, there are
459 now three forms:
461 $rh_xxx: and $rheader_xxx: give the original content of the header
462 line(s), with no processing at all.
464 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
465 then decode base64 or quoted-printable "words" within the header text,
466 but do not do charset translation.
468 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
469 standard character set.
471 If you have previously been using $h_ expansions to access the raw
472 characters, you should change to $rh_ instead.
4743. When Exim creates an RFC 2047 encoded word in a header line, it labels it
475 with the default character set from the headers_charset option instead of
476 always using iso-8859-1.
4784. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
479 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
480 called TMPDIR, and if it finds it is different, it changes its value.
4825. Following a discussion on the list, the rules by which Exim recognises line
483 endings on incoming messages have been changed. The -dropcr and drop_cr
484 options are now no-ops, retained only for backwards compatibility. The
485 following line terminators are recognized: LF CRLF CR. However, special
486 processing applies to CR:
488 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
489 nor a local message in the state where . is a terminator.
491 (ii) If a bare CR is encountered in a header line, an extra space is added
492 after the line terminator so as not to end the header. The reasoning
493 behind this is that bare CRs in header lines are most likely either
494 to be mistakes, or people trying to play silly games.
4966. The code for using daemon_smtp_port, local_interfaces, and the -oX options
497 has been reorganized. It is supposed to be backwards compatible, but it is
498 mentioned here just in case I've screwed up.
502Version 4.20
5051. I have tidied and re-organized the code that uses alarm() for imposing time
506 limits on various things. It shouldn't affect anything, but if you notice
507 processes getting stuck, it may be that I've broken something.
5092. The "arguments" log selector now also logs the current working directory
510 when Exim is called.
5123. An incompatible change has been made to the appendfile transport. This
513 affects the case when it is used for file deliveries that are set up by
514 .forward and filter files. Previously, any settings of the "file" or
515 "directory" options were ignored. It is hoped that, like the address_file
516 transport in the default configuration, these options were never in fact set
517 on such transports, because they were of no use.
519 Now, if either of these options is set, it is used. The path that is passed
520 by the router is in $address_file (this is not new), so it can be used as
521 part of a longer path, or modified in any other way that expansion permits.
523 If neither "file" nor "directory" is set, the behaviour is unchanged.
5254. Related to the above: in a filter, if a "save" command specifies a non-
526 absolute path, the value of $home/ is pre-pended. This no longer happens if
527 $home is unset or is set to an empty string.
5295. Multiple file deliveries from a filter or .forward file can never be
530 batched; the value of batch_max on the transport is ignored for file
531 deliveries. I'm assuming that nobody ever actually set batch_max on the
532 address_file transport - it would have had odd effects previously.
5346. DESTDIR is the more common variable that ROOT for use when installing
535 software under a different root filing system. The Exim install script now
536 recognizes DESTDIR first; if it is not set, ROOT is used.
5387. If DESTDIR is set when installing Exim, it no longer prepends its value to
539 the path of the system aliases file that appears in the default
540 configuration (when a default configuration is installed). If an aliases
541 file is actually created, its name *does* use the prefix.
544Version 4.14
5471. The default for the maximum number of unknown SMTP commands that Exim will
548accept before dropping a connection has been reduced from 5 to 3. However, you
549can now change the value by setting smtp_max_unknown_commands.
5512. The ${quote: operator has been changed so that it turns newline and carriage
552return characters into \n and \r, respectively.
5543. The file names used for maildir messages now include the microsecond time
555fraction as well as the time in seconds, to cope with systems where the process
556id can be re-used within the same second. The format is now
558 <time>.H<microsec>P<pid>.<host>
560This should be a compatible change, but is noted here just in case.
5624. The rules for creating message ids have changed, to cope with systems where
563the process id can be re-used within the same second. The format, however, is
564unchanged, so this should not cause any problems, except as noted in the next
5675. The maximum value for localhost_number has been reduced from 255 to 16, in
568order to implement the new message id rules. For operating systems that have
569case-insensitive file systems (Cygwin and Darwin), the limit is 10.
5716. verify = header_syntax was allowing unqualified addresses in all cases. Now
572it allows them only for locally generated messages and from hosts that match
573sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
5757. For reasons lost in the mists of time, when a pipe transport was run, the
576environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
577form used in Message-ID: header lines). The 'E' has been removed.
580Version 4.11
5831. The handling of lines in the configuration file has changed. Previously,
584macro expansion was applied to logical lines, after continuations had been
585joined on. This meant that it could not be used in .include lines, which are
586handled as physical rather than logical lines. Macro expansion is now done on
587physical lines rather than logical lines. This means there are two
590 (a) A macro that expands to # to turn a line into a comment now applies only
591 to the physical line where it appears. Previously, it would have caused
592 any following continuations also to be ignored.
594 (b) A macro name can no longer be split over the boundary between a line and
595 its continuation. Actually, this is more of a bug fix. :-)
5972. The -D command line option must now all be within one command line item.
598This makes it possible to use -D to set a macro to the empty string by commands
599such as
601 exim -DABC ...
602 exim -DABC= ...
604Previously, these items would have moved on to the next item on the command
605line. To include spaces in a macro definition item, quotes must be used, in
606which case you can also have spaces after -D and surrounding the equals. For
609 exim '-D ABC = something' ...
6113. The way that addresses that redirect to themselves are handled has been
612changed, in order to fix an obscure bug. This should not cause any problems
613except in the case of wanting to go back from a 4.11 (or later) release to an
614earlier release. If there are undelivered messages on the spool that contain
615addresses which redirect to themselves, and the redirected addresses have
616already been delivered, you might get a duplicate delivery if you revert to an
617earlier Exim.
6194. The default way of looking up IP addresses for hosts in the manualroute and
620queryprogram routers has been changed. If "byname" or "bydns" is explicitly
621specified, there is no change, but if no method is specified, Exim now behaves
622as follows:
624 First, a DNS lookup is done. If this yields anything other than
625 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
626 getipnodebyname() (or gethostbyname() on older systems) and the result of the
627 lookup is the result of that call.
629This change has been made because it has been discovered that on some systems,
630if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
631returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
632first, and only if that gives a definite "no such host" to try the local
6355. In fixing the minor security problem with pid_file_path, I have removed some
636backwards-compatible (undocumented) code which was present to ease conversion
637from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
638contain "%s", which was replaced by the port number for daemons listening on
639non-standard ports. In Exim 4, such daemons do not write a pid file. The
640backwards compatibility feature was to replace "%s" by nothing if it occurred
641in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
642the problem by removing the backwards compatibility feature. Thus, if you still
643have "%s" somewhere in a setting of pid_file_path, you should remove it.
6456. There has been an extension to lsearch files. The keys in these files may
646now be quoted in order to allow for whitespace and colons in them. This means
647that if you were previously using keys that began with a doublequote, you will
648now have to wrap them with extra quotes and escape the internal quotes. The
649possibility that anybody is actually doing this seems extremely remote, but it
650is documented just in case.
653Version 4.10
656The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
657to better reflect its function. The OS-specific files have been updated. Only
658if you have explicitly set this in your Makefile (highly unlikely) do you need
659to change anything.