This is PGP 5.0, a significant step forward from 2.6.*

CHANGES:

There are a number of large changes from the 2.6.2 distribution.  Most
notable is that the command line has changed substantially.  See
the pgp(1) man page for a discussion of how to use the new command
line.

Also, to allow easy interoperation with older versions on the same
system, a number of filename changes have been made.

NEW FEATURES:

PGP 5.0 contains support for new encryption methods (most notably
DSS/Diffie-Hellman), and built-in keyserver support.  Also, the
command line has been redesigned to be more Unix and scripting
friendly.

WWW: http://www.pgpi.com/