Krack attack affected the WPA2 standard as it relates to secure wireless networks. The Netvanta 3140 will not be receiving an update as it is not affected by this vulnerability. Adtran posted a security notice on the affected products, which products have software, and which affected products will not be receiving an update due to EoL. Said document can be found HERE
KRACK affects a vulnerability in the WPA encryption algorithm for wi-fi. The 3140 is not a wireless device and therefore isn't affected.