You can enter a purchase invoice that is subject to a payment discount if you pay it within a particular number of days. In previous releases, such an invoice would remain outstanding if you did pay within that period, because not the entire invoice amount had been paid, and you then had to manually post the outstanding discount amount.
From this release, the payment discount will be posted automatically to the ledger account 'Creditor discounts' and the open item will be closed. If you selected a purchase invoice subject to a payment discount on the Payments form, then the Payment difference field on the display panel will show 'Payment discount' to let you know that the payment discount will be posted and the open item will be closed.