# 2016-10-11

* Assigning a nonexistent custom field to a contact, estimate, (recurring) sales invoice or identity now returns a `404` HTTP response with a helpful error message instead of a generic `500` error.
* In many error cases the error response hash now also contains a `symbolic` entry with machine readable error details. See the [documentation](/api/sales_invoices/#post_sales_invoices_example1) for an example.