+PH/19 When an Exim process that is running as root has to create an Exim log
+ file, it does so in a subprocess that runs as exim:exim so as to get the
+ ownership right at creation (otherwise, other Exim processes might see
+ the file with the wrong ownership). There was no test for failure of this
+ fork() call, which would lead to the process getting stuck as it waited
+ for a non-existent subprocess. Forks do occasionally fail when resources
+ run out. I reviewed all the other calls to fork(); they all seem to check
+ for failure.
+
+PH/20 When checking for unexpected SMTP input at connect time (before writing
+ the banner), Exim was not dealing correctly with a non-positive return
+ from the read() function. If the client had disconnected by this time,
+ the result was a log entry for a synchronization error with an empty
+ string after "input=" when read() returned zero. If read() returned -1
+ (an event I could not check), uninitialized data bytes were printed.
+ There were reports of junk text (parts of files, etc) appearing after
+ "input=".
+
+PH/21 Added acl_not_smtp_mime to allow for MIME scanning for non-SMTP messages.
+
+PH/22 Added support for macro redefinition, and (re)definition in between
+ driver and ACL definitions.
+
+PH/23 The cyrus_sasl authenticator was expanding server_hostname, but then
+ forgetting to use the resulting value; it was using the unexpanded value.
+
+PH/24 The cyrus_sasl authenticator was advertising mechanisms for which it
+ hadn't been configured. The fix is from Juergen Kreileder, who
+ understands it better than I do:
+
+ "Here's what I see happening with three configured cyrus_sasl
+ authenticators configured (plain, login, cram-md5):
+
+ On startup auth_cyrus_sasl_init() gets called for each of these.
+ This means three calls to sasl_listmech() without a specified mech_list.
+ => SASL tests which mechs of all available mechs actually work
+ => three warnings about OTP not working
+ => the returned list contains: plain, login, cram-md5, digest-md5, ...
+
+ With the patch, sasl_listmech() also gets called three times. But now
+ SASL's mech_list option is set to the server_mech specified in the the
+ authenticator. Or in other words, the answer from sasl_listmech()
+ gets limited to just the mech you're testing for (which is different
+ for each call.)
+ => the return list contains just 'plain' or 'login', 'cram-md5' or
+ nothing depending on the value of ob->server_mech.
+
+ I've just tested the patch: Authentication still works fine,
+ unavailable mechs specified in the exim configuration are still
+ caught, and the auth.log warnings about OTP are gone."
+
+PH/25 When debugging is enabled, the contents of the command line are added
+ to the debugging output, even when log_selector=+arguments is not
+ specified.
+
+PH/26 Change scripts/os-type so that when "uname -s" returns just "GNU", the
+ answer is "GNU", and only if the return is "GNU/something" is the answer
+ "Linux".
+
+PH/27 $acl_verify_message is now set immediately after the failure of a
+ verification in an ACL, and so is available in subsequent modifiers. In
+ particular, the message can be preserved by coding like this:
+
+ warn !verify = sender
+ set acl_m0 = $acl_verify_message
+
+ Previously, $acl_verify_message was set only while expanding "message"
+ and "log_message" when a very denied access.
+
+PH/28 Modified OS/os.c-Linux with
+
+ -#ifndef OS_LOAD_AVERAGE
+ +#if !defined(OS_LOAD_AVERAGE) && defined(__linux__)
+
+ to make Exim compile on kfreebsd-gnu. (I'm totally confused about the
+ nomenclature these days.)
+
+PH/29 Installed patch from the Sieve maintainer that adds the options
+ sieve_useraddress and sieve_subaddress to the redirect router.
+
+PH/30 In these circumstances:
+ . Two addresses routed to the same list of hosts;
+ . First host does not offer TLS;
+ . First host accepts first address;
+ . First host gives temporary error to second address;
+ . Second host offers TLS and a TLS session is established;
+ . Second host accepts second address.
+ Exim incorrectly logged both deliveries with the TLS parameters (cipher
+ and peerdn, if requested) that were in fact used only for the second
+ address.
+
+PH/31 When doing a callout as part of verifying an address, Exim was not paying
+ attention to any local part prefix or suffix that was matched by the
+ router that accepted the address. It now behaves in the same way as it
+ does for delivery: the affixes are removed from the local part unless
+ rcpt_include_affixes is set on the transport.
+
+PH/32 Add the sender address, as F=<...>, to the log line when logging a
+ timeout during the DATA phase of an incoming message.
+
+PH/33 Sieve envelope tests were broken for match types other than :is. I have
+ applied a patch sanctioned by the Sieve maintainer.
+
+PH/34 Change 4.50/80 broke Exim in that it could no longer handle cases where
+ the uid or gid is negative. A case of a negative gid caused this to be
+ noticed. The fix allows for either to be negative.
+
+PH/35 ACL_WHERE_MIME is now declared unconditionally, to avoid too much code
+ clutter, but the tables that are indexed by ACL_WHERE_xxx values had been
+ overlooked.
+
+PH/36 The change PH/12 above was broken. Fixed it.
+
+PH/37 Exim used to check for duplicate addresses in the middle of routing, on
+ the grounds that routing the same address twice would always produce the
+ same answer. This might have been true once, but it is certainly no
+ longer true now. Routing a child address may depend on the previous
+ routing that produced that child. Some complicated redirection strategies
+ went wrong when messages had multiple recipients, and made Exim's
+ behaviour dependent on the order in which the addresses were given.
+
+ I have moved the duplicate checking until after the routing is complete.
+ Exim scans the addresses that are assigned to local and remote
+ transports, and removes any duplicates. This means that more work will be
+ done, as duplicates will always all be routed, but duplicates are
+ presumably rare, so I don't expect this is of any significance.
+
+ For deliveries to pipes, files, and autoreplies, the duplicate checking
+ still happens during the routing process, since they are not going to be
+ routed further.
+