1.6.8 Hearing of a witness no longer necessary 

The testimony of a witness summoned to oral proceedings is heard if the facts which the testimony is supposed to corroborate are relevant to the decision (see E‑IV, 1.2). Therefore, the witness is not heard if the facts to be proved are no longer relevant due to developments before or during oral proceedings before the witness is heard. This may be the case for example if the public availability of the relevant prior art has been proven by another means of evidence or if the patent is to be revoked on another ground for opposition and the patent proprietor submits no admissible auxiliary requests for the assessment of which the testimony would be relevant.