d) Failure to hold oral proceedings 

In T 170/21 the decision to refuse the application without summoning the applicant to oral proceedings had taken the appellant by surprise, thereby depriving it of a further opportunity to present its final comments and/or its final fallback positions and denying it the right to be heard as guaranteed by Art. 113(1) EPC. This conclusion was in line with established case law of the boards of appeal; see for example T 1423/13, which dealt with almost identical circumstances (refusal without summoning to previously announced oral proceedings).