EVANOUELLETTE,
Per the Adtran End-of-Life section, specifically for the NetVanta 160:
"Last Date of Support (AKA End of Life Date (EOL))
The last date to receive service and support for the
product. After this date, all support services for the
product are unavailable, and the product becomes
obsolete. This is the official End of Life Date of the
product. 03/31/2017"
Typically at this point the last version of firmware / software for products are removed from the Support Community. I see your options as: 1 - Someone sends you the firmware, sorry I do not have a copy. 2 - Your client upgrades their Wi-Fi network.
Regards,
BMULLAR