It would appear that currently only the 'language' property is the only property that might be sent in an Update message. To trigger that event you might need to have an initial callflow that starts out in one language and then if the caller presses a number to be in another language, then transfer them to a callflow in a different language.

Ref: [Session Walkthrough]
(https://developer.genesys.cloud/devapps/audiohook/session-walkthrough#update-transaction)

Genesys Audio Hook introduced Update Transaction Message recently and this change is breaking our existing system. We are trying to working around this situation but we are unable to see Update Transaction Message in the audio hook in our environment. We want to know how to enable Update Transaction Message for our audio hook or what are steps that needs to taken so that we start seeing Update Transaction Message.