+PH/17 If a delivery to a pipe, file, or autoreply was deferred, Exim was not
+ using the correct key (the original address) when searching the retry
+ rules in order to find which one to use for generating the retry hint.
+
+PH/18 If quota_warn_message contains a From: header, Exim now refrains from
+ adding the default one. Similarly, if it contains a Reply-To: header, the
+ errors_reply_to option, if set, is not used.
+
+PH/19 When calculating a retry time, Exim used to measure the "time since
+ failure" by looking at the "first failed" field in the retry record. Now
+ it does not use this if it is later than than the arrival time of the
+ message. Instead it uses the arrival time. This makes for better
+ behaviour in cases where some deliveries succeed, thus re-setting the
+ "first failed" field. An example is a quota failure for a huge message
+ when small messages continue to be delivered. Without this change, the
+ "time since failure" will always be short, possible causing more frequent
+ delivery attempts for the huge message than are intended.
+
+PH/20 Added $auth1, $auth2, $auth3 to contain authentication data (as well as
+ $1, $2, $3) because the numerical variables can be reset during some
+ expansion items (e.g. "match"), thereby losing the authentication data.
+
+PH/21 Make -bV show the size of off_t variables so that the test suite can
+ decide whether to run tests for quotas > 2G.
+
+PH/22 Test the values given for quota, quota_filecount, quota_warn_threshold,
+ mailbox_size, and mailbox_filecount in the appendfile transport. If a
+ filecount value is greater than 2G or if a quota value is greater than 2G
+ on a system where the size of off_t is not greater than 4, a panic error
+ is given.
+
+PH/23 When a malformed item such as 1.2.3/24 appears in a host list, it can
+ never match. The debug and -bh output now contains an explicit error
+ message indicating a malformed IPv4 address or mask.
+
+PH/24 An host item such as 1.2.3.4/abc was being treated as the IP address
+ 1.2.3.4 without a mask. Now it is not recognized as an IP address, and
+ PH/23 above applies.
+
+PH/25 Do not write to syslog when running in the test harness. The only
+ occasion when this arises is a failure to open the main or panic logs
+ (for which there is an explicit test).
+
+PH/26 Added the /no_tell option to "control=freeze".
+
+PH/27 If a host name lookup failed very early in a connection, for example, if
+ the IP address matched host_lookup and the reverse lookup yielded a name
+ that did not have a forward lookup, an error message of the form "no IP
+ address found for host xxx.xxx.xxx (during SMTP connection from NULL)"
+ could be logged. Now it outputs the IP address instead of "NULL".
+
+PH/28 An enabling patch from MH: add new function child_open_exim2() which
+ allows the sender and the authenticated sender to be set when
+ submitting a message from within Exim. Since child_open_exim() is
+ documented for local_scan(), the new function should be too.
+
+PH/29 In GnuTLS, a forced expansion failure for tls_privatekey was not being
+ ignored. In both GnuTLS and OpenSSL, an expansion of tls_privatekey that
+ results in an empty string is now treated as unset.
+
+PH/30 Fix eximon buffer overflow bug (Bugzilla #73).