Minor rounding change for custom line item discounts in POS 11.5
Shopify developer change
MerchantDiff detected this entry in Shopify's official developer changelog on April 27, 2026.
This Shopify update is categorized as API, Update, POS Extensions.
What changed
Starting with POS version 11.5, we are updating the internal calculation method for custom fixed-amount line item discounts. These discounts will now be applied on a per-unit basis rather than across the entire line. Note that this change only affects fixed-amount discounts; percentage discounts remain unchanged. If your app uses setLineItemDiscount or bulkSetLineItemDiscounts from the Cart API with a FixedAmount discount type, you can continue to pass the total discount amount for the line item as you currently do. The POS system will automatically handle the conversion.
Who is affected
Developers maintaining Shopify POS apps or POS UI extensions should review this change.
What action may be needed
Review the official Shopify entry, confirm whether the change touches your app, and test the affected workflow before your next relevant deployment.
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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