The decisions provide initial legal certainty on issues of disclosure, interpretation, infringement, and directors’ liability.

1. Context and Significance

In October 2025, the Court of Appeal of the Unified Patent Court (UPC) issued its long-awaited first substantive decisions: (i) the decision in Seoul Viosys (UPC_CoA_764/2024 & 774/2024) concerning added subject-matter, and (ii) the decision in Philips v. Belkin (UPC_CoA_534/2024, 19/2025, 683/2024) addressing infringement, claim interpretation, and directors’ liability.

These judgments – coming just over two years after the launch of the UPC system – mark the beginning of a true harmonisation of substantive patent law within the framework of the UPCA.

2. The Seoul Viosys Decision (CoA 764/2024 & 774/2024)

In its first substantive decision, the Court of Appeal dealt with the question of whether the granted claims extended beyond the content of the application as originally filed. The defendant in the infringement proceedings had filed a counterclaim for revocation based on added subject-matter. While the court of first instance had upheld the patent, the Court of Appeal reversed that decision and revoked the patent.

The Court confirmed that the relevant test for added subject-matter under Article 65(2) UPCA and Article 138(1)(c) EPC corresponds to the so-called “gold standard” of the EPO: the skilled person must be able to derive the claimed subject-matter directly and unambiguously from the original disclosure, taking into account their common general knowledge. An implicit disclosure is sufficient only if it is the inevitable consequence of what is expressly disclosed.

Particular importance was given to the issue of divisional applications. The Court held that the disclosure must be found not only in the divisional application itself, but also in any earlier application in the chain of filings – including parent and grandparent applications. The deletion of features or the combination of elements from different embodiments may amount to an impermissible intermediate generalisation unless the remaining combination is itself clearly and unambiguously disclosed as a general teaching. Applying this test, the Court found that the patent contained added subject-matter and therefore revoked it.

Commentators have noted that the reasoning closely follows EPO case law, while at the same time representing an autonomous application of these principles under the UPCA. The decision thus establishes a strict disclosure standard as the benchmark for assessing patent validity before the UPC.

3. The Philips v. Belkin Decision (CoA 534/2024, 19/2025 & 683/2024)

In its second substantive decision, the Court of Appeal dealt with several appeals arising from an infringement case before the Munich Local Division. Philips had asserted European Patent EP 2 867 997 against several Belkin entities and their managing directors. The first instance had found infringement and issued injunction, recall, and destruction orders. The Court of Appeal used the case to clarify key issues of infringement law – in particular, claim interpretation, the notion of “offering,” and personal liability of managing directors.

4. Claim Interpretation

The Court confirmed a functional, expert-oriented approach to claim interpretation. The key question was whether a transmitter that only sends a signal of “acceptance” fulfils a claim feature referring to “acceptance or rejection.” The Court of Appeal held that it does, as the technical purpose – the communication of the negotiation result – is achieved. The decisive point is the understanding of the skilled person in light of the description; statements made by the applicant during prosecution may serve as supporting evidence but cannot independently limit the scope of protection.

Accordingly, the Court clarified that the objective technical meaning derived from the description remains decisive, and that the prosecution history does not constitute a primary source of interpretation. This approach – largely in line with expectations – enhances legal certainty for future interpretation disputes before the UPC.

5. “Offering” as an Act of Infringement under Article 25(a) UPCA

The Court of Appeal interpreted the concept of “offering” in an economic and autonomous manner. A legally binding offer is not required; even a mere presentation or invitation to submit an offer can constitute an act of infringement if it enables potential customers to acquire the patented product. Consequently, online product listings, catalogues, or advertisements may amount to infringement, even where no sale has yet occurred.

This broad interpretation – largely consistent with German law – reflects the realities of modern marketing practices. Companies operating within the UPC territory must therefore continue to review their advertising and sales activities carefully to avoid infringement risks.

6. Liability of Managing Directors

A central aspect of the Belkin judgment was the personal liability of managing directors. The Court clarified that mere corporate office does not give rise to liability. Personal liability exists only where the director deliberately uses the company as an instrument of infringement or, being aware of the infringement and its unlawfulness, fails to take reasonable steps to prevent it. This is likely to result, overall, in a management liability regime that is somewhat less strict than under German law, yet still one to be taken seriously.

The Court further emphasised that obtaining well-founded legal advice – for example, a non-infringement or freedom-to-operate opinion – may shield against liability, at least until a first-instance court has confirmed the infringement. As Philips had failed to show intentional or knowing participation by the Belkin directors, the Court lifted the injunctions issued against them.

7. Relationship with National Decisions

Belkin relied on an earlier German decision in which a Philips infringement claim had been dismissed. The Court of Appeal, unsurprisingly, rejected this argument: the res judicata effect of national judgments extends only to their operative part within the respective national territory and between the same parties. The reasoning and interpretation of a national court are not binding on the UPC, which under Articles 34 and 65 UPCA exercises independent jurisdiction.

8. Conclusion

The first substantive decisions of the UPC Court of Appeal – Seoul Viosys and Philips v. Belkin – may hold few surprises in substance, but they nonetheless represent an important milestone in the development of European patent litigation. They provide initial legal certainty on issues of disclosure, interpretation, infringement, and directors’ liability. Further decisions of the Court of Appeal in the coming months are eagerly awaited and will continue to shape the UPC’s emerging jurisprudence.

All reasonably available evidence and arguments should be submitted as early as possible. Submitting prior art and arguments based on it at a later stage risks their rejection. Early investment is essential; the respective initial pleadings in the proceedings should be as airtight as possible.

In a decision of 7 March 2025 (UPC_CFI_459/2023), the LD Duesseldorf held in its headnotes that

“Strategic maneuvering aimed at achieving surprise effects is foreign to the rules of procedure”

and thus rejected new invalidity attacks that had only been raised in the respective oral hearing.
While such maneuvering was not uncommon in, for example, national German patent litigation, the UPC has already gone beyond such tame limitations, and has shaped the RoP via interpretation in a way that can only be described as “front loaded” in litigation speak, a term that is also expressively used in the case law of the CoA itself, see e.g. headnotes of CoA, order of 18 September 2024, UPC_CoA_264/2024 et al.
Meaning, that parties should not only abstain from raising entirely new arguments in the oral hearing, but arguments should instead be raised as early as possible. Such an approach ensures that the lines of argumentation in the course of a proceeding take the shape of a pyramid – becoming ever more focused on the contentious issues – rather than that of a branched tree, which was not too seldom the case in for example national German litigation.

General guidelines

While this approach is generally very reasonable in light of the aim of procedural efficiency, its application in practice can create headaches for parties and their representatives about what to search for and what to include in their first submissions. Since the details are far from being resolved, the general takeaway is

• Evidence for infringement, that was or could have been made available at the time of filing the statement of claim, risks being rejected if introduced later
• As far as infringement of a dependent claim could be argued, this should be done in the statement of claim
• In case there is already pre-trial exchange of the parties on infringement, evidence, validity, claim construction, prior art etc., this exchange should be fully included and also addressed in the statement of claim
• This also means, that in the absence of such pre-trial exchange, not every conceivable line of claim construction must be presented in the statement of claim, but a short description of the parts of the patent specification and the drawings which support the claimant’s claim construction
• Likewise, not every conceivable evidence must be presented, but every alleged fact should be supported by at least one piece of evidence, and may it just be a written testimony by the party
• The statement of defense must address all arguments, and all reasonably conceivable counterarguments should be included, with the weaker ones at least in a skeleton form
• This also applies to the counterclaim for revocation: all reasonably conceivable combinations of prior art for attacking inventive step should be included, with the weaker ones at least in skeleton form. Dependent claims should also be attacked, as far as possible
• All prior art than can be found, must be found!

The latter point cannot be stressed enough. In a recent order, the CoA confirmed a first instance decision that had rejected an application to amend a counterclaim for revocation, which was filed two days after the counterclaim. The counterclaimant had become aware of additional prior art, that a service provider tasked with researching prior art had seemingly overlooked, as this prior art popped up in an unrelated search of the counterclaimants patent attorney, which however used the same search string as the service provider (2 September 2025, UPC_CoA_807/2025).

Conclusion

This means that when properly researching prior art, not only should a reliable and able external service provider be commissioned, but its results should be double- and crosschecked by attorneys, if the budget allows. This further means that arguments that an external service provider did insufficient work and thus not being initially aware of certain prior art is not the fault of the respective party will likely not be heard, and that therefore not only the general quality of the provider should be considered, but also whether useful prior art might be found in specific domains (i.e. East Asian countries, academic publications) where different service providers might have the edge.

Lastly, this front-loaded approach means for claimants, that when the UPC or a national forum would both be available, specifically the German courts, and at least initial investment in the proceedings shall be on the lower side, the German courts might be more suitable, in order not to risk that a case is lost not because it had no merit, but because the investment could not match the front loading requirements of the UPC.