It appears Avaya sold the networking product line to Extreme Networks. And
Product documentation, downloads, knowledge articles and technical support can be requested via www.extremenetworks.com
https://support.avaya.com/support/en/download/1399823629353?productId=P0609
Maybe you can try contacting them.
Yeah hiding DNS queries is just one part of the equation. It has to be coupled with other techs/techniques to really achieve privacy.