+JH/37 Bug 2552: Fix the check on spool space during reception to use the SIZE
+ parameter supplied by the sender MAIL FROM command. Previously it was
+ ignored, and only the check_spool_space option value for the required
+ leeway checked.
+
+JH/38 Fix $dkim_key_length. This should, after a DKIM verification, present
+ the size of the signing public-key. Previously it was instead giving
+ the size of the signature hash.
+
+JH/39 DKIM verification: the RFC 8301 restriction on sizes of RSA keys is now
+ the default. See the (new) dkim_verify_min_keysizes option.
+
+JH/40 Fix a memory-handling bug: when a connection carried multiple messages
+ and an ACL use a lookup for checking either the local_part or domain,
+ stale data could be accessed. Ensure that variable references are
+ dropped between messages.
+
+JH/41 Bug 2571: Fix SPA authenticator. Running as a server, an offset supplied
+ by the client was not checked as pointing within response data before
+ being used. A malicious client could thus cause an out-of-bounds read and
+ possibly gain authentication. Fix by adding the check.
+
+JH/42 Internationalisation: change the default for downconversion in the smtp
+ transport to be "if needed". Previously it was "as previously set" for
+ the message, which usually meant "if needed" for message-submission but
+ "no" for everything else. However, MTAs have been seen using SMTPUTF8
+ even when the envelope addresses did not need it, resulting in forwarding
+ failures to non-supporting MTAs. A downconvert in such cases will be
+ a no-op on the addresses, merely dropping the use of SMTPUTF8 by the
+ transport. The change does mean that addresses needing conversion will
+ be converted when previously a delivery failure would occur.
+