Disable update notification emails.

This snippet will disable update notification emails.

<?php

add_filter('auto_core_update_send_email', 'wpb_stop_auto_update_emails', 10, 4);

function wpb_stop_update_emails($send, $type, $core_update, $result)
{
    if (!empty($type) && $type == 'success') {
        return false;
    }
    return true;
}

add_filter('auto_plugin_update_send_email', '__return_false');

add_filter('auto_theme_update_send_email', '__return_false');