When deleting a contact (and the company also, if it's the last contact) our webhook does not receive a message with reason 'deleted'.
Other changes to contacts or companies works correctly, we receive messages with reason 'updated'. So the webhook communication seems to work just fine.
Reading the documentation about webhooks, one of the reason-values is 'deleted', so I think this ought to work, but it doesn't. Why is this not sent to the webhook-URL ?