b) Rule 99(1)(b) EPC 

Under R. 99(1)(b) EPC, the notice of appeal shall contain an indication of the decision impugned.

According to J 16/94, (OJ 1997, 331), for a notice of appeal to comply with Art. 108, first sentence, EPC 1973 and R. 64(b) EPC 1973, it had to express the definite intention to contest an appealable decision. An appeal filed as a subsidiary request, i.e. conditional on the main request not being allowed by the department of first instance, was therefore inadmissible. This was because there should be legal certainty as to whether or not a decision was contested. This was confirmed by T 460/95 date: 1997-10-20 (OJ 1998, 588).

In T 2716/16 the board stated that the fact that the appellant referred to the opposition division's decision in its notice of appeal erroneously as a decision on the revocation of the patent (the opposition division rejected the opposition) was immaterial to the admissibility of its appeal (see T 1/88 in which the appellant (opponent) had also erroneously referred to the opposition division's decision to reject the opposition as a decision to reject the application).