1.6.8 Hearing of a witness no longer necessary 

A witness summoned to oral proceedings is heard if the facts which their testimony is supposed to corroborate are relevant to the decision (see E‑IV, 1.2). This means they are not heard if the facts to be proved are no longer relevant due to developments before or during oral proceedings before they are 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 does not submit any admissible auxiliary requests in relation to which the testimony would still be relevant.