- * PSPP can now read and write ZCOMPRESSED system files, a new format
- variant that compresses data much more effectively than the
- previous form of compression (which is still supported).
+ * Support for new system file variants:
+
+ - PSPP can now read and write ZCOMPRESSED system files, which
+ compress data much more effectively than older "compressed"
+ files. (The older format is still supported.)
+
+ - PSPP can now decrypt encrypted system files, using the new
+ pspp-convert utility. The encrypted system file format is
+ unacceptably insecure, so to discourage its use PSPP and PSPPIRE
+ do not directly read or write this format.