-As a special case of format conversion, @command{pspp-convert} can
-decrypt an encrypted SPSS system file. Specify the encrypted file as
-@var{input}. The output will be the equivalent plaintext SPSS system
-file. You will be prompted for the password (or use @option{-p},
-documented below).
+@command{pspp-convert} can convert most input formats to most output
+formats. Encrypted system file and syntax files are exceptions: if
+the input file is in an encrypted format, then the output file must be
+the same format (decrypted). To decrypt such a file, specify the
+encrypted file as @var{input}. The output will be the equivalent
+plaintext file. You will be prompted for the password (or use
+@option{-p}, documented below).