1.5 Summoning of parties, witnesses and experts 

The parties, witnesses and experts to be heard must be summoned to appear to give evidence on the date fixed. The summons must be notified and must give at least two months' notice unless the party, witness or expert has agreed to a shorter period. The summons must contain:

(i)an extract from the order to take evidence, indicating in particular the date, time and place of the investigation ordered, whether it will be conducted by videoconference and stating the facts on which parties, witnesses and experts are to be heard 

(ii)the names of the parties to the proceedings and particulars of the rights which the witnesses or experts may invoke (see E‑IV, 1.10)

(iii)an indication that a party, witness or expert who has been summoned to appear before the EPO on its premises may be heard by videoconference at their request and 

(iv)an indication that any party, witness or expert may request to be heard by the competent court of their country of residence and a requirement that they inform the EPO within a time limit to be fixed by the EPO whether they are prepared to appear before it (see E‑IV, 3.2.2 (iii) and E‑IV, 3.2.2 (iv)).

Even if evidence is not taken at oral proceedings, all parties to the proceedings may attend an investigation. Parties not summoned are informed of the investigation and of their right to attend within the period laid down in Rule 118(2).