This endpoint asynchronously updates specific data elements for existing SKUs in a DRAFT version's product catalog. Unlike the POST endpoint, this endpoint does not create new products — it only modifies data elements for SKUs that already exist in the catalog.

The mode query parameter controls the update behavior: UPDATE merges the provided data with existing data, while REPLACE replaces all entries within each included data category.

This operation returns a request_id for tracking. Requests targeting an ACTIVE or DEACTIVATED version will fail.