+Version 4.51
+------------
+
+The format in which GnuTLS parameters are cached (in the file gnutls-params in
+the spool directory) has been changed. The new format can also be generated
+externally, so it is now possible to update the values from outside Exim. This
+has been implemented in an upwards, BUT NOT downwards, compatible manner.
+Upgrading should be seamless: when Exim finds that it cannot understand an
+existing cache file, it generates new parameters and writes them to the cache
+in the new format. If, however, you downgrade from 4.51 to a previous release,
+you MUST delete the gnutls-params file in the spool directory, because the
+older Exim will not recognize the new format.
+
+
+Version 4.50
+------------
+
+The exicyclog script has been updated to use three-digit numbers in rotated log
+files if the maximum number to keep is greater than 99. If you are already
+keeping more than 99, there will be an incompatible change when you upgrade.
+You will probably want to rename your old log files to the new form before
+running the new exicyclog.
+
+