A document submitted under Art. 115 EPC 1973 during opposition proceedings, but after the time limit for filing the notice of opposition had expired, was discussed in the appeal proceedings, but not taken into account as it was found not proven to be publicly available at the relevant time and thus did not form part of the state of the art (T 314/99).

In T 637/09 the board took into account, when exercising its discretion, that it should not accord the third party within the meaning of Art. 115 EPC more favourable treatment than would be given to an actual party seeking to introduce such submissions at that stage of the proceedings. The third-party observations filed shortly before the oral proceedings were not admitted into the proceedings since their admission would have accorded the third party more favourable treatment than would have been given to an actual party (see also T 346/15).

In T 953/02 the respondent had challenged the submission under Art. 115 EPC 1973 because of a signature which was deficient, i.e. not that of a natural person. The submission by the third party was filed substantially less than one month before the oral proceedings. The board did not admit it into the proceedings. This also removed any need to consider the arguments set out in the respondent's letter or the literature enclosed.

In T 771/13 the observations were received by the EPO some days before oral proceedings. The novelty objection was not based on state of the art under the EPC. Moreover, the remaining documents and objections were not prima facie more relevant than those raised previously. Consequently there was no need to decide whether or not to admit these late-filed observations.

In T 1528/13, not only had the third-party observations been presented well after the notice of appeal had been filed but neither they nor the evidence produced in support of them appeared prima facie any more relevant than the submissions already on file.