+PH/45 When the plaintext authenticator is running as a client, the server's
+ challenges are checked to ensure they are valid base64 strings. By
+ default, the authentication attempt is cancelled if an invalid string is
+ received. Setting client_ignore_invalid_base64 true ignores these errors.
+ The decoded challenge strings are now placed in $auth1, $auth2, etc. as
+ they are received. Thus, the responses can be made to depend on the
+ challenges. If an invalid string is ignored, an empty string is placed in
+ the variable.
+
+PH/46 Messages that are created by the autoreply transport now contains a
+ References: header, in accordance with RFCs 2822 and 3834.
+
+PH/47 Added authenticated_sender_force to the smtp transport.
+