Fails to load jQuery script in the Footer

Hi,
I still don’t understand why my jQuery script is still loaded in my header section !

function update_jquery() {
	if (!is_admin()) {
		wp_deregister_script('jquery');
		wp_register_script('jquery','/scripts/jquery-2.1.1.min.js','',null,true);
		wp_enqueue_script('jquery');
	}
}
add_action('wp_enqueue_scripts', 'update_jquery');

This is what I checked :

• – The function above is correct (I verified that the code was correct using the WordPress Codex).
• – I tested to remove the above function that deregister jQuery to load the WordPress default jQuery library (in case my function was incorrect).
• – wp_footer() is well present in the loaded file footer.php from my theme files.
• – I tested all the following workarounds to call jQuery in the footer :

1. How to enqueue the bundled jQuery in footer – The Right Way
2. Getting all JavaScript into the Footer in WordPress ?

Thanks for your support.