R. 113 EPC says that decisions, summonses, notices and communications from the EPO must be signed by, or bear the seal of, the employee responsible. In T 390/86 the board decided that if the decision of a particular division was to be legally valid it had to bear the signatures of the members who had been appointed to that division to decide the issue.
Source: http://www.epo.org/law-practice/legal-texts/html/caselaw/2019/e/clr_iii_k_3_3_1.htm
Date retrieved: 17 May 2021