In T 2638/16, the patent proprietor had filed its reply to the grounds of appeal late (shortly after expiry of the period prescribed in Art. 12(1)(c) RPBA 2020), its request for an extension having been refused. The board observed that the purpose of Art. 12 RPBA 2020 was to oblige the parties to present a complete case at the outset of the proceedings in order to ensure the board had an appeal file containing comprehensive submissions from each party and to prevent tactical abuses of procedure. Exercising its discretion under Art. 13(1) RPBA 2020, the board took into account that the reply had been received immediately after notification of the refusal of the request for an extension and so at a still early stage in the proceedings and that the belated filing had not prevented it from considering the complete cases of all the parties. It could see no indication that the late filling had been a tactical abuse of procedure or impaired procedural economy. It thus took the reply, and a document filed with it, into account under Art. 13(1) RPBA 2020.