With the exception of renewal fees (see 3.1.73.7), due dates for the payment of fees related to Unitary Patents follow the same principle as for European patent applications, namely the first day on which the fees may validly be paid, not the last day of a period for such payment. If no due date is specified, the fee is due on the date of receipt of the request for the service incurring the fee concerned (Art. 4 RFees; see EPC Guidelines, A‑X, 5.1.1).
Rule 134 EPC applies mutatis mutandis for the calculation of valid payment of fees.The amount of the renewal fee to be paid is determined by the RFeesUPP. The applicable amount is the one in force on the date on which the payment is made (Art. 2 RFeesUPP).