I uninstalled my current version of kindle 4 pc, installed the latest straight from amazon (
https://www.amazon.com/gp/kindle/pc/download), registered successfully, then opened the installer for 1.17.44183 (from the links to amazon's website) and it promptly opened up kindle set to version 1.17 and downloaded books in .azw format once more. Success!
Although you do have to wonder how long this will work. Will I be forced to buy a kindle e-ink just to get useful files?