We updated the Sandbox behavior debtorAccount OPTIONAL on POSTinitPaymentRequest as preview for the upcoming updates in Real API’s.
For the domestic payments in Real API we will be introducing validations that only eligible accounts will be used for the created payments. Therefore with this Sandbox deployment we are introducing validation rules which will return only domestic accounts held in domestic currency on Sandbox for payments with creditorAccount.currency – domestic AND instructedAmount.currency – domestic.