_maybe_update_core()

function _maybe_update_core() {
	// include an unmodified $cp_version
	include( ABSPATH . WPINC . '/version.php' );

	$current = get_site_transient( 'update_core' );

	if ( isset( $current->last_checked, $current->version_checked ) &&
		12 * HOUR_IN_SECONDS > ( time() - $current->last_checked ) &&
		$current->version_checked == $cp_version ) {
		return;
	}
	wp_version_check();
}