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## API Updates for August 15, 2024

**API**

* We are happy to announce that the [Cart](/developer/api-reference/rest/admin/management/carts) and [Checkout](/developer/api-reference/rest/admin/management/checkouts) API now supports optimistic concurrency control. This feature helps prevent lost updates caused by concurrent requests overriding changes made by others. If the `version` number provided by an API client does not match the version on the server, the request will be rejected, allowing the client to handle it accordingly.

* We added new formats for product codes upc, mpn, and gtin for [Catalog V3 Products](/developer/api-reference/rest/admin/catalog/products) and [Product variant](/developer/api-reference/rest/admin/catalog/product-variants) APIs.

**Themes**

* Updated the Product Recommendations (Beta) docs. We now have [reference code for Cornerstone](https://github.com/bigcommerce/cornerstone/pull/2470) available to modify your Stencil theme when you [request recommendations](/developer/docs/beta/product-recommendations/request-recommendations).

**Bug Fixes**

* Corrected the [Updated an order](/developer/api-reference/rest/admin/management/orders) endpoint to specify that we remove discounts from line items changed in the request, not the whole order.

**Enhancements**

* We created a [Create a Bulk Pricing Rule](/developer/api-reference/rest/admin/catalog/products/bulk-pricing-rules) endpoint for our documentation. Thanks @altugyavuz7.