2.4.10 Patent proprietor unaware of opposition proceedings

In T 1529/20 the appellant argued that they received neither the communication informing them about the notice of opposition (EPO Form 2316), nor the communication under R. 79(1) EPC, which would have given them the opportunity to file observations and amendments in response to the opposition (EPO Form 2317), nor the decision of the opposition division revoking their patent. The board held that, as a matter of principle, the notice of initiation of proceedings must be duly served on the persons/legal entities against whom the decision takes effect or who/which may be adversely affected by it. The communication under R. 79(1) EPC was not a mere formality. Rather, it had the function of allowing the patent proprietor to both contribute to the opposition division's appreciation of the facts and to defend its interests. The board found that the missing opportunity of the appellant to present their arguments during the opposition proceedings amounted to a substantial procedural violation in the sense of Art. 113(1) EPC. See also chapters III.S.2.1. "Notification by postal services", III.S.5. "Burden of proof and safeguards", IV.C.2.2.8f) "No burden of proof with regard to negative facts" and IV.C.6.4. "EPO communication concerning submissions by the other party – adequate opportunity to reply".