Firefox extension automatically Update (silently without popup and any notification)

I followed the instructions on http://www.borngeek.com/firefox/automatic-firefox-extension-updates/ for setting up extension updates. I uploaded update.rdf and e开发者_Go百科xtension XPI file to a local server (App Engine server). I started the browser and after some time the Add-on Manager shows available updates. But they are not installed automatically (clicking the "Update" button is still necessary).

What do I need to do to have updates install automatically?

Most extensions require Firefox to be restarted after an update. So the Add-on Manager will detect and download updates but it will not interrupt the user. The updates will install automatically when Firefox is started next time.

Only exception are bootstrapped extensions that don't require a restart (this includes all add-ons created with the Add-on SDK). These extensions can be updated while Firefox is running. However, they also have a whole lot of limitations.