Isn't there an in place update of an existing database without dump and restore now for quite some versions (http://www.postgresql.org/docs/9.3/static/pgupgrade

Isn't there an in place update of an existing database without dump and restore now for quite some versions (http://www.postgresql.org/docs/9.3/static/pgupgrade.html http://www.postgresql.org/docs/9.3/static/pgupgrade.html)? A tool which keeps the relation files, but builds new system catalogs around them? It had the impression that this tool would be very fast, but a bit risky. The linked article makes it sound like there is a need for local replication in order to do an update without (much) downtime. Is this just a (less risky!) alternative to the available in place update?