How to disable the "Your site has updated to WordPress x.y.z" admin email?

Question

Using the automatic update of my self-hosted WordPress blogs, I configured automatic updates of both the WordPress core as well as WordPress plugins and themes (through this plugin).

Whenever a core update occurs, I get an email like:

Your site has updated to WordPress 3.9.2

Howdy! Your site at http://example.org has been updated automatically to WordPress 3.9.2.

No further action is needed on your part. For more on version 3.9.2, see the About WordPress screen: http://example.org/wp-admin/about.php

If you experience any issues or need support, the volunteers in the WordPress.org support forums may be able to help. https://wordpress.org/support/

The WordPress Team

I understand that I can completely disable administrative notification emails but I would prefer to only disable the above notification.

Therefore my question is:

How to disable update notification emails in WordPress?

Answer 1

In your functions.php add:

add_filter( 'auto_core_update_send_email', '__return_false' );

Answer 2

An alternative is to create a simple Must-use plugin so this doesn't depend on the theme.

Create a file wp-content/mu-plugins/disable-auto-update-mail.php

<?php
/*
Plugin Name: Disable Auto Update Mails
Plugin URI: http://wordpress.stackexchange.com/questions/157056
Version: 1.0
Author: kraftner
AuthorURI: http://wordpress.stackexchange.com/users/47733/kraftner
*/

add_filter( 'auto_core_update_send_email', '__return_false' );

This can't be disabled by a user and works independent from any themes.