---
title: >-
  POS UI extensions 2026-07 uses per-unit fixed-amount line item discounts -
  Shopify developer changelog
description: >-
  Shopify’s developer changelog documents all changes to Shopify’s platform.
  Find the latest news and learn about new platform opportunities.
source_url:
  html: >-
    https://shopify.dev/changelog/pos-ui-extensions-2026-07-uses-per-unit-fixed-amount-line-item-discounts
  md: >-
    https://shopify.dev/changelog/pos-ui-extensions-2026-07-uses-per-unit-fixed-amount-line-item-discounts.md
metadata:
  effectiveApiVersion: 2026-07
  affectedApi:
    - displayName: POS Extensions
      handle: pos-extensions
  primaryTag:
    displayName: API
    handle: api
  secondaryTag:
    displayName: Breaking API Change
    handle: breaking-api-change
  indicatesActionRequired: true
  createdAt: '2026-06-10T15:35:03-04:00'
  postedAt: '2026-07-08T12:00:00-04:00'
  updatedAt: '2026-07-08T09:33:19-04:00'
  effectiveAt: '2026-07-15T00:00:00-04:00'
---

July 8, 2026

Tags:

* Action Required
* POS Extensions
* 2026-07

# POS UI extensions 2026-07 uses per-unit fixed-amount line item discounts

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. To apply a $5.00 total discount to a line item with quantity 2, you must instead pass `'2.50'` as the per-unit discount.

## What you need to do

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. If your app currently calculates discounts as a total line discount, compute the per-unit discount before calling `setLineItemDiscount` or `bulkSetLineItemDiscounts` — for example, by dividing the total discount by the line item quantity.

If the total discount does not divide evenly by the line item quantity, choose a rounded per-unit value that matches your app’s intended discount behavior and ensures the final discount is consistent with your logic.

For more information, see the [Cart API reference](https://shopify.dev/docs/api/pos-ui-extensions/2026-07/target-apis/contextual-apis/cart-api).