Refunds from a customer's own change now wait for your approval

When a customer applies a discount or swaps an item for something cheaper, the refund they are owed no longer leaves your store on its own. The order page shows "A refund is waiting for your approval" with an Approve refund button. Approving reads the amount Shopify currently shows as owed and refunds it once to the original payment method; a second click does nothing. If you would rather refund these automatically, turn on "Refund customers automatically" in the new Refunds section of Global settings. It is off by default.