SELECT extversion FROM pg_extension WHERE extname = 'rdf_fdw';
 extversion 
------------
 2.1
(1 row)

CREATE SERVER fs FOREIGN DATA WRAPPER rdf_fdw
OPTIONS (endpoint 'http://example.com/sparql');
CREATE FOREIGN TABLE ft (
  s rdfnode OPTIONS (variable '?s'),
  p rdfnode OPTIONS (variable '?p'),
  o rdfnode OPTIONS (variable '?o')
) SERVER fs OPTIONS 
  (sparql 'SELECT ?s ?p ?o WHERE { }');
ALTER EXTENSION rdf_fdw UPDATE TO '2.2';
SELECT extversion FROM pg_extension WHERE extname = 'rdf_fdw';
 extversion 
------------
 2.2
(1 row)

DROP SERVER fs CASCADE;
NOTICE:  drop cascades to foreign table ft