EPO board of appeal refers major claim-construction, added-matter, and referral questions to Enlarged Board of Appeal

Context: ArcelorMittal’s EP3587104B1 (“Coated steel strips”) has been the subject of European Patent Office (EPO) opposition proceedings brought by POSCO. After the Opposition Division maintained the patent in amended form, both ArcelorMittal and POSCO appealed, bringing the dispute before the Technical Board of Appeal (TBA). The patent belongs to a multi-generation patent family, making questions of claim interpretation and added matter central to the appeal. In interlocutory decision T 873/24, the Board concluded that guidance from the Enlarged Board of Appeal (EBA) is needed on both the substantive added-matter issues raised by the case and the circumstances under which a referral to the EBA may be considered necessary.