While this article provides methods to obtain IAP-207 firmware at no monetary cost, you must respect copyright law.
Some IAP models fall under a lifetime warranty policy that provides access to "conservative" or "standard" software builds without a separate support contract. Airheads Community Aruba 207 Series Wireless Access Point - Installation Guide aruba iap 207 firmware free
Look for the or ArubaOS US Encryption (depending on your regulatory domain) matching the Alcatraz architecture. While this article provides methods to obtain IAP-207