I have read the documentation here:

https://developers.facebook.com/docs/whatsapp/cloud-api/guides/send-messages#

And I'm trying to do this:

curl -X POST "https://graph.facebook.com/v21.0/012345678901234/messages" -H "Authorization: Bearer <USER_ACCESS_TOKEN>" -H "Content-Type: application/json" -d '{ "messaging_product": "whatsapp", "recipient_type": "individual", "to": "012345678901", "context": { "message_id": "wamid.HBgNNTQ5MzUxNjA3NzE5OBUCABEYEjNBMURDQzNEQTE5QjIyM0EwOQA=" }, "type": "text", "text": { "body": "Please reply to this message" } }'

But the message that arrives is an ordinary text message, with no context bubble.