Here are the steps that I must follow to upgrade an addons on Odoo 11 :
1. Go to Apps tab.
2. Remove the only Apps filter (because I upgrade a simple module).
3. Search and find my module.
4. Click on my module to open its panel.
5. And finally Click on upgrade.
6. (optionally) restart the Odoo server...
Do you know a quicker/proper way ?
(My question is similar to this one which dates from 2014 and seems outdated.)
Restart the server.
open terminal
goto odoo directory
sudo su postgres
./odoo-bin -i addon_name -d db_name
Use i for install and -u for update the addons.