Don,
I believe 9.8.3 is released after the 9.9 GA release. So, 9.9 release notes doesn't have 9.8.3 firmware under the upgrade paths list.
However, you can upgrade the ZD to 9.9.1 version from 9.8.3 with out any issues.
Use chrome/firefox browser for the upgrade.
Also, as Max mentioned, check the supported APs list.
Thanks
Anusha