Updates existing catalog rows of one saved branch (vendor_uid), identified by vendor_catalog_uid: you can change the linked Zuper or supplier option, SKU, unit of measure, cost and remarks. Each row's cost is refreshed from the supplier's price for that branch when one is returned (not for a branch that does not stock the item); otherwise the vendor_cost you send is stored. Zuper may reuse a supplier price answer for up to 15 minutes, so a price can be that old. When a row's option mapping changes, rows at the provider's other branches that used the old supplier option are re-linked in the same request (mapping_changes, affected_vendors); when its unit changes, the product's rows at other branches are re-priced in the new unit in the background (uom_propagation). All rows are saved together or not at all, and only one update per branch can run at a time (429 otherwise). Instead of an option UID, an entry can name the Zuper option in zuper_product_option_name: Zuper reuses the product option with that name or creates it, and reports the outcome in data.zuper_option_resolutions. Options created this way are kept even if the rest of the update then fails. Admin only: the API key must belong to an admin user; other roles receive 405 Access Denied.