We recommend that Marketplace sellers use the new MP_ITEM_MATCH version 4.0 that has removed ProductTaxCode, product subcategory attributes, and support for additional Identifiers. Tax codes are now auto-generated and assigned to items during the item setup process. Sellers can select one of the provided categories in the spec based on their product category. ISBN and EAN identifiers are now supported along with existing GTIN and UPC Identifiers. additionalOfferAttributes and additionalProductAttributes are added to the spec for any optional additional attributes. Sellers can override a product tax code that was auto-assigned when the item was initially set up. The MP_ITEM_MAINTENANCE spec version 4.1 has the ProductTaxCode attribute that you can use to override a tax code.For more information and to download the Item spec versions, see in the Guide.