For our customization want to completely disable all types of automatic updates, core or otherwise, add the following to your wp-config.php file
define( 'AUTOMATIC_UPDATER_DISABLED', true );
This code will completely disable all types of automatic updates.
Have any doubt, then comment here!
You might like to put this to true:
define( ‘CORE_UPGRADE_SKIP_NEW_BUNDLED’, true );
Keeps wp-content clean / no Twentyseventeen theme etc 😉