it's recommended to use the value B<no>, especially if combined with
the B<-selfsign> command line option.
-=item B<serialfile>
+=item B<serial>
a text file containing the next serial number to use in hex. Mandatory.
This file must be present and contain a valid serial number.
+=item B<crlnumber>
+
+a text file containing the next CRL number to use in hex. The crl number
+will be inserted in the CRLs only if this file exists. If this file is
+present, it must contain a valid CRL number.
+
=item B<x509_extensions>
the same as B<-extensions>.