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If one or more tokens are available, onetime_notification_available is set to true on the conversation. This property is available in the tenanttenants/<uuid>/conversations/<uuid>/details/ endpoint. Note: this will not affect the expiry of the conversation.
Using the token
A one-time notification token will automatically be used if the conversation is expired and one of these tokens is available. No special request parameters are required.
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Clicking the ‘Notify Me’ button on the Facebook website does not call our webhook. Clicking/tapping in the Facebook Messenger app does work. See https://developers.facebook.com/support/bugs/214460430006606310445676685298/ for status.