Newer IOX-BT (GXSBT1) does not pick up IOX-BT beacon packets that older versions of IOX-BT pick up. With older versions of IOX-BT we are seeing the custom data. With GXSBT1 we are not seeing any custom data. We are following the Add-On Protocol - BLE Advertisement https://developers.geotab.com/hardware/protocolReference/ble/index.html