diff --git a/contrib/pg_upgrade/function.c b/contrib/pg_upgrade/function.c
new file mode 100644
index 54f139a..4505e51
*** a/contrib/pg_upgrade/function.c
--- b/contrib/pg_upgrade/function.c
*************** check_loadable_libraries(void)
*** 228,235 ****
  		char	   *cmd = (char *) pg_malloc(8 + 2 * llen + 1);
  		PGresult   *res;
  
  		strcpy(cmd, "LOAD '");
! 		PQescapeStringConn(conn, cmd + 6, lib, llen, NULL);
  		strcat(cmd, "'");
  
  		res = PQexec(conn, cmd);
--- 228,251 ----
  		char	   *cmd = (char *) pg_malloc(8 + 2 * llen + 1);
  		PGresult   *res;
  
+ 		/*
+ 		 *	In Postgres 9.0, Python 3 support was added, and to do that, a
+ 		 *	plpython2u language was created with library name plpython2.so
+ 		 *	as a symbolic link to plpython.so.  In Postgres 9.1, only the
+ 		 *	plpython2.so library was created, and both plpythonu and
+ 		 *	plpython2u pointing to it.  For this reason, any reference to
+ 		 *	library name "plpython" in an old PG <= 9.1 cluster must look
+ 		 *	for "plpython2" in the new cluster.
+ 		 */
+ 		if (GET_MAJOR_VERSION(old_cluster.major_version) < 901 &&
+ 			strcmp(lib, "$libdir/plpython") == 0)
+ 		{
+ 			lib = "$libdir/plpython2";
+ 			llen = strlen(lib);
+ 		}
+ 
  		strcpy(cmd, "LOAD '");
! 		PQescapeStringConn(conn, cmd + strlen(cmd), lib, llen, NULL);
  		strcat(cmd, "'");
  
  		res = PQexec(conn, cmd);