Customer Account API Customer.lastIncompleteCheckout and Checkout types removed in 2026-10
Shopify developer change
MerchantDiff detected this entry in Shopify's official developer changelog on July 06, 2026.
This Shopify update is categorized as Action Required, API, Breaking API Change, Customer Account API, 2026-10.
What changed
As of Customer Account API version 2026-10, the deprecated Customer.lastIncompleteCheckout field is removed. This also removes the now-unreachable Customer Account API Checkout type subtree, including: Checkout Checkout.appliedGiftCards AppliedGiftCard AvailableShippingRates CheckoutLineItem CheckoutLineItemConnection CheckoutLineItemEdge ShippingRate The Customer.lastIncompleteCheckout field was previously deprecated and returned null. This change removes stale Checkout Classic schema from the Customer Account API.
Who is affected
Developers building customer account experiences or extensions should review this change.
What action may be needed
If your app queries Customer.lastIncompleteCheckout or any nested fields on the returned Checkout object, update your queries before upgrading to API version 2026-10. Remove selections such as: customer { lastIncompleteCheckout { id appliedGiftCards { id } } } There is no replacement field in the Customer Account API. If you need active cart or checkout state for a buyer storefront experience, use Storefront API cart flows instead.
Use the official Shopify entry below as the source of truth for technical implementation details, affected APIs, migration instructions and deadlines.
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