Summary: LOC wants a field that allows a library to see default sort order. They want an itemsort order ID that allows them to preserve the item sort order they have with Voyager. They want that order reflected in the edge-rtac response too so that it displays as expected on Locate. 

Task supports gathering requirements

• Adding the sortID how to pass it to edge-rtac. How to prevent impact to FOLIO UI?

• How can libraries preserve the current default item display order?

• Is there any value in allowing libraries to set default item display order based on barcode? Or other fields? 

• Migration and release upgrade handling

• Update https://folio-org.atlassian.net/browse/UXPROD-1625 based on requirements analysis.

Requirements:

1. Add a numeric sort order field to the item record

   1. Do we need to expose this field on the UI?

2. For existing items: Populate numeric sort order field with current sort (Barcode)

3. For newly created items, increment the sort order field

4. Allow for libraries to change the sort order (numeric value) via API

   1. No validation needed for deduplication

   2. No UI mechanism to re-sort needed for this current implementation; will be handled in UXPROD-1625: Re-order Item records

      Draft

5. Add sort order to the RTAC response

6. Mapping

   1. Upon migration, allow for libraries to map sort order values from previous system to FOLIO

Definition of done: Confirm requirements with LOC before getting high-level estimates.