is there example of update skript?

Hello

I am playing with extensions implemented in plpgsql. I am checking update.

I have a simple extension

file gdlib--1.1.sql
CREATE OR REPLACE FUNCTION gdlib_version()
RETURNS numeric AS $$
SELECT 1.1;
$$ LANGUAGE sql;

CREATE OR REPLACE FUNCTION hello(text)
RETURNS text AS $$
SELECT 'Hello, ' || $1 || ' from gdlib ' || gdlib_version();
$$ LANGUAGE sql;

file gdlib--1.0.sql
CREATE OR REPLACE FUNCTION gdlib_version()
RETURNS numeric AS $$
SELECT 1.0;
$$ LANGUAGE sql;

CREATE OR REPLACE FUNCTION hello(text)
RETURNS text AS $$
SELECT 'Hello, ' || $1 || ' from gdlib ' || gdlib_version();
$$ LANGUAGE sql;

I created a empty update files (it's probably wrong)

postgres=# SELECT * FROM pg_extension_update_paths('gdlib');
source | target | path
--------+--------+----------
1.0 | 1.1 | 1.0--1.1
1.1 | 1.0 | 1.1--1.0
(2 rows)

Issue

After ALTER EXTENSION gdlib UPDATE TO '1.1'

I have 1.0 function still?

I expected a refresh 1.1 sql script, but it was newer loaded

What are correct steps?

Regards

Pavel Stehule