a) General 

According to the established case law of the boards of appeal on Art. 114(2) EPC, filing new facts, documents and evidence would be considered to be in due time, if the filing was occasioned by an argument or a point raised by another party or in the appealed decision and could not have been filed before under the circumstances of the case. However, in order not to deprive the other parties of their right to verify the new evidence or to prevent the board from ensuring that the proceedings are conducted expeditiously, such facts and evidence have to be submitted once they are available and once it has become clear that they were relevant (T 201/92; T 951/91, OJ 1995, 202; T 502/98; T 1421/05; T 730/07; T 320/08; T 976/10). Late filing is justifiable if it is an appropriate and immediate reaction to developments in the previous proceedings (T 855/96). Late filing is also admissible in order to support the reasoning to date (T 561/89) and to prove claimed common general knowledge, if challenged (T 106/97, T 1076/00).

In T 815/14 the board, assessing the situation under Art. 12(4) RPBA 2007, held that an appellant who had lost the opposition proceedings should be given the opportunity to fill the gaps in its arguments by presenting further evidence in the second instance (see also T 1146/06, T 406/09 and T 54/16; for the case law on Art. 12(4) RPBA 2007, see chapter V.A.5.11.).

In T 1045/08 the board stated that where a party files new requests in appeal proceedings the other party must have the possibility of responding to these including the filing of new prior art documents, particularly when some of the amendments to the claims of the requests are based on features taken from the description of the patent. In this situation the concept of "late filed" must be considered relatively since the documents could not have been filed earlier because the party could not know the content of the future requests of the other party.

On the requirement that documents filed as an objectively appropriate reaction to the contested decision also be (sufficiently or prima facie) relevant for the outcome of the assessment of the claimed subject-matter's patentability, see e.g. T 1817/15 and T 1380/04. See also chapter V.A.5.13.2 "Relevance".