In T 2884/18 the appeal was rejected as inadmissible. The board considered the statement of grounds of appeal insufficient as it primarily discussed only the opposition division's finding that the asserted public prior use had not been adequately demonstrated, while failing to duly substantiate a lack of novelty in view of that public prior use. The board explained that, for a case based on chains of reasoning to be complete, as Art. 108 EPC and Art. 12 RPBA 2020 required, it was necessary to set out all the facts that led to the asserted legal outcome only when considered cumulatively. The approach had to mirror that in proceedings against a decision listing various alternative reasons why a patent could not be granted or maintained. In this respect, the case law of the boards of appeal had it that an appeal could be deemed sufficiently substantiated only if it addressed all the grounds precluding patentability. Only then had a case for setting the decision aside been made (see T 922/05). The same had to apply in reverse if several grounds cast doubt on the patentability of a maintained patent only when considered cumulatively, as was the case here: prior use forming part of the prior art and prior use anticipating the invention. If out of a number of facts having to be considered cumulatively in order to alter the decision just one was sufficiently substantiated, the appeal was inadmissible.