POS UI extensions 2026-07 uses per-unit fixed-amount line item discounts
Shopify developer change
MerchantDiff detected this entry in Shopify's official developer changelog on July 08, 2026.
This Shopify update is categorized as Action Required, API, Breaking API Change, POS Extensions, 2026-07.
What changed
Starting with POS UI extensions API version 2026-07, FixedAmount line item discounts passed to setLineItemDiscount and bulkSetLineItemDiscounts from the Cart API must represent a per-unit discount. Why it's changing In API version 2026-04 and earlier, apps could pass a total fixed discount for the entire line item, and Shopify POS automatically converted it to a per-unit value. In API version 2026-07, this conversion no longer occurs. The value you pass is interpreted directly as the discount applied to each unit in the line item. For example, in API version 2026-07, if you pass '5.00' on a line item with quantity 2, POS applies a $5.00 discount to each unit, for a $10.00 total discount.
Who is affected
Developers maintaining Shopify POS apps or POS UI extensions should review this change.
What action may be needed
This change only affects FixedAmount line item discounts. Percentage discounts are not affected. Apps using API version 2026-04 or earlier do not need to make any changes. Apps adopting API version 2026-07 must update their discount calculations before using the new version.
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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