- Introduced cart API methods shopify.cart.addLineItemSellingPlan and shopify.cart.removeLineItemSellingPlan for managing subscription selling plans on line items.
- Extended the LineItem interface with selling‑plan related fields (requiresSellingPlan, hasSellingPlanGroups, sellingPlan).
- Requires POS UI Extension 2025-10+ and Shopify POS 10.13+; using these APIs on older versions will block checkout.