<?php
/**
 * Plugin Name: Limit Core Update Emails
 * Description: Keeps WordPress core failure and critical update emails enabled, while suppressing successful-update and new-version-available notifications.
 */

add_filter( 'send_core_update_notification_email', '__return_false' );

add_filter(
	'auto_core_update_send_email',
	static function ( $send, $type ) {
		return 'success' !== $type;
	},
	10,
	2
);