The Limits of G 10/91: T 0967/23 on Fresh Grounds and Appeal Amendments
Board 3.5.01 clarifies that avoiding a fresh ground of opposition under G 10/91 does not guarantee admissibility on appeal. A new inventive step attack based on a prior novelty document is an amendment to the appeal case.
The doctrinal boundary between a fresh ground of opposition and a mere amendment to a party's appeal case has been a recurring procedural tension since the Enlarged Board of Appeal issued G 10/91. In T 0967/23, Board 3.5.01 pushes this boundary into sharp focus, clarifying that escaping the strictures of G 10/91 does not guarantee a free pass under the Rules of Procedure of the Boards of Appeal.
How does a new inventive step attack bypass G 10/91 but fail the RPBA?
The opponent attacked the granted patent for an elevator power supply system on novelty during the opposition proceedings, relying on document D1. On appeal, they introduced a new inventive step attack based on the same document. The opponent argued that under established case law, specifically T 131/01, an inventive step attack based on a document previously used for novelty is not a fresh ground for opposition. Therefore, they contended, it could be examined without the patent proprietor's agreement.
The Board acknowledged the Enlarged Board of Appeal framework established in G 10/91, G 1/95, and G 7/95. However, the panel drew a strict line between the requirement for patentee agreement and the admissibility of amendments on appeal. The Board held that the question of whether a fresh ground of opposition has been raised must be distinguished from the question of whether there has been an amendment to a party's appeal case (reasons 16). Admissibility remains a separate, independent issue subject to the Board's discretion under Article 114(2) EPC and Articles 12 and 13 RPBA.
Why did the Board distinguish the procedural facts from T 131/01?
The opponent relied heavily on T 131/01 to justify admitting the new attack. The Board identified a critical factual divergence. In T 131/01, the opponent had actually submitted the inventive step arguments during the opposition proceedings, but the opposition division had incorrectly exercised its discretion not to admit them.
In the present case, the lack of inventive step starting from D1 was raised for the very first time on appeal. Because the proprietor's and the opposition division's position that D1 did not anticipate claim 1 was known before the oral proceedings in opposition, the Board concluded that the inventive step attack could and should have been filed at that stage. Consequently, the attack was rejected as an inadmissible amendment to the appeal case under Articles 12(4) and 12(6) RPBA.
Why did the novelty attack based on D1 fail?
The substantive novelty dispute centered on whether D1 disclosed a power supply system configured to supply "protective extra-low voltage" to the elevator car, and whether it featured two voltage monitors configured to detect an over-voltage condition "at the switch mode power supply".
The opponent argued that D1 met the voltage supply feature because a switch for closing a series chain was located on the car. The Board rejected this, noting that the extra-low voltage in D1 was only supplied to safety relays, not for operating the car's components or a power outlet. Regarding the monitors, the opponent argued that measuring downstream of a resistor still constituted measuring at the power supply. The Board disagreed, finding that because of the considerable length of the cables to the elevator car, the downstream circuit could not be modelled as a mere voltage divider, as parasitic inductance and capacitance could become significant (reasons 8).
How did the Board define the objective technical problem over D6?
The opponent also pursued an inventive step attack combining D6 or D7 with D3. They formulated the objective technical problem broadly as "how to improve protection". The Board found this formulation too broad. Looking at the differentiating features and the patent's general teaching, the Board defined the objective technical problem more specifically as how to improve protection of the elevator car and/or of its users (reasons 25). Because D3 concerned solely the protection of a generic power source itself and not the protection of loads fed by the power source, the skilled person would not have considered it relevant.
What must opponents change after T 0967/23?
Opponents can no longer rely on the absence of a "fresh ground of opposition" as a shield for late-filed attacks. If a novelty attack is filed in opposition, the corresponding inventive step fallback must be explicitly substantiated before the opposition division. Waiting until the statement of grounds of appeal to pivot from novelty to inventive step will be treated as an amendment to the appeal case, subject to the strict preclusion rules of Article 12(6) RPBA. Practitioners must ensure that all permutations of their attacks are fully developed at the first instance, as the procedural hurdle of the RPBA operates entirely independently of the Enlarged Board of Appeal's framework for fresh grounds.