Hello,
The Autoconn feature came after AA3170. You would need to use a draft release of the new upcoming AA32xx firmware. Please file a ticket support at: https://www.iot747.com/support/open.php, stating company name, project and teh team will give you an early release which has the AUTOCONN_BCAST config. It is a Config like any other Config. Thanks.
IOT747 Support