@Ian Porter - The feature of webhook support for alarms/events is still being developed. The exact ETA of the release with that support is unknown yet.
Currently, only the following message types are supported for XiqCreateWebhookSubscriptionRequest.
[ LOCATION_AP_CENTRIC, LOCATION_CLIENT_CENTRIC, AUDIT_LOG_ALL ]
The above information can be found from "https://api.extremecloudiq.com/swagger-ui/index.html?configUrl=/openapi/swagger-config#/".