According to one of the discussion threads in Netscape's Message Board, Netscape 8.1.3 is scheduled to be released on 1st April. The file is now available on Netscape's FTP server, but Netscape has not yet made the announcement (at time of posting).
No release notes at time of posting, but it is believed to be a security maintenance.
Screenshot of Netscape 8.1.3:
Netscape 8.1.3 is based on Gecko rv 1.7.5 (20070321).
Stay tuned for more information.