+PH/16 As discussed on the list in Nov/Dec: Exim no longer looks at the
+ additional section of a DNS packet that returns MX or SRV records.
+ Instead, it always explicitly searches for A/AAAA records. This avoids
+ major problems that occur when a DNS server includes only records of one
+ type (A or AAAA) in an MX/SRV packet. A byproduct of this change has
+ fixed another bug: if SRV records were looked up and the corresponding
+ address records were *not* found in the additional section, the port
+ values from the SRV records were lost.
+
+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.
+
+