The developer API v1.1 has been updated to let you assign custom IDs to records you create via the API. This comes in handy when integrating Elorus with 3rd-party software, to help you map Elorus records with data stored in external systems.
A new field, named custom_id, has been added to all the invoices,
credit notes, estimates, bills, contacts and inventory items (products) endpoints.
As of today, this field is not available to the Elorus user interface and may only be
set and retrieved via the API.