To configure the payment escalation (dunning), go to "Payment > Payment > Payment Escalation" in the settings. Here you first set the days on which an action is to be carried out after the payment is overdue. Then select the desired action. There you have the choice whether a webhook should be triggered or a reminder created. The Webhook "PaymentEscalated" does not represent a separate dunning level, but can be configured as an intermediate step or at the same time with the action "Create reminder".
With the action "Create reminder" you can select the desired reminder template for the respective escalation level.
Then click on the "+" symbol to add the step. Finally, save your settings with "Save".
You can also set a threshold value from which the payment escalation should be started for each used currency. If you send your reminders by letter post, you can avoid sending reminders that have a lower value than the postage costs.
Simply select any amount and click on "Save".