This is required for the icat.server to see a new authenticator. If you are just updating an existing restful authenticator then the run.properties of the icat.server will not need changing.
Assuming that you still have the installation directory for icat.server then edit the run.properties to refer to the new authenticator and type: ./setup install
Use testicat (which is installed with ICAT) with one of the entries in the database PASSWD table. It should report that it logs in but may or may not have the permission to run the rest of the test. If it does not report that it has logged in then please check the server.log and the authn_anon.log files which can both be found in the logs directory below your domain.