We generally expect this to return one of [``['Completed', 'Pending', 'Failed']``](https://github.com/Shopify/shopify/blob/5eef2c6916bdb443917321c222d1592995148014/app/models/offsite_payment_gateway.rb#L77). I suppose other values from ``params['status']`` will just cause the notification to be ignored, so perhaps that's reasonable then.