Wittenstein v Vestas Wind Systems (CFI, 2 September 2026)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

By decision of 2 September 2026 (UPC_CFI_523/2025), the Munich Central Division, on Wittenstein’s stand-alone revocation action, revoked Vestas Wind Systems’ European patent with unitary effect EP 4 226 039 (wind turbine power transmission system) in respect of claims 21 and 22 only, and maintained it as amended by auxiliary request 1. The attacks on claim 1 for lack of novelty and inventive step and the non-entitlement ground were rejected. The decision clarifies the burden of proof for non-entitlement under Art. 138(1)(e) EPC and the claimant’s interest in challenging dependent claims in a stand-alone action. The outcome is consistent with that reached by the EPO opposition division (paragraph 175).

Facts and procedure

In 2025 Wittenstein brought an action for revocation of the patent in its entirety, granted on 18 September 2024, for lack of novelty, lack of inventive step, insufficiency and non-entitlement. Vestas sought dismissal and, in the alternative, maintenance on seven auxiliary requests. In parallel, the EPO opposition division maintained the patent on 24 June 2026 in amended form corresponding to auxiliary request 1, a decision not yet final. The oral hearing took place on 8 July 2026. The value of the dispute had been set at EUR 500,000.

The applicable law

The Munich section has jurisdiction under Art. 33(4) UPCA, the patent falling within IPC class F03D (paragraphs 13 to 16). Validity is assessed under Art. 65 UPCA and Art. 138(1)(a), (b) and (e) EPC, together with Arts 54, 56, 60(1) and 83 EPC, the amendments under Arts 84 and 123(2) and (3) EPC. The admission of late submissions falls, in particular, under Rule 9.2 RoP.

Question

Is claim 1 novel and inventive over D20, D11, D15, D14a and GRU5? Is Vestas entitled to the patent? Are dependent claims 21 and 22 sufficiently disclosed, and should the division examine them although the independent claim is valid?

Decision

Several sections of Wittenstein’s rejoinder were disregarded as late-filed, while the attacks based on GRU5 were admitted (paragraphs 17 to 25). Wayback Machine screenshots can be enough to establish that a document was made available, the point being left open for a figure in D20 (paragraphs 54 to 61). D20 and D11 do not anticipate, and an oral disclosure was not proven (paragraphs 70 to 89). On inventive step, D15 is a suitable starting point but leads the skilled person away from the claimed solution. The combinations with D14a, D20, D11 and GRU5 fail for want of a pointer or for missing features (paragraphs 110 to 144). Non-entitlement requires that the proprietor have no rights to the patent at all. The burden lies on the claimant, the registered proprietor benefiting from a presumption (Rule 8.5(c) RoP), and the evidence shows Vestas to be at least a co-inventor (paragraphs 154 to 162). A claimant in a stand-alone action may have a legitimate interest in a ruling on dependent claims, which the division examined in the exercise of its discretion (paragraph 167). Claims 21 and 22 conflict with claim 19 and are insufficiently disclosed (paragraphs 168 to 171). Auxiliary request 1, which deletes them, complies with Arts 84 and 123 EPC (paragraph 172). Wittenstein bears 90% of Vestas’ costs and Vestas 10% of Wittenstein’s, subject to a ceiling of EUR 56,000 (paragraphs 176 and 177).

Key points for practice

• A non-entitlement attack fails where the proprietor holds part of the rights, for instance as a co-inventor.
• In a stand-alone revocation action the division may rule on the validity of dependent claims even where the independent claim is upheld.
• Screenshots from online archives may suffice to establish when a document was made available.
• Practical point: new attacks raised for the first time in the rejoinder on the application to amend are likely to be disregarded, they should be made in the reply.

Provisions applied

Agreement on a Unified Patent Court

Arts 32(1)(d), 33(4), 65 and 69

Rules of Procedure

Rules 8.5(c), 9.2, 43.3 and 118.5

European Patent Convention

Arts 54, 56, 60, 83, 84, 123 and 138

Case law cited

Nanostring v 10x Genomics, Court of Appeal, 26 February 2024, OrthoApnea, Court of Appeal, 21 November 2024, Mammut v Ortovox, Court of Appeal, 25 September 2024, Insulet v EOFlow, Court of Appeal, 30 April 2025, Avago v Tesla, Hamburg Local Division, 26 August 2024, DISH v AYLO, Mannheim Local Division, 6 June 2025, Meril v Edwards, Court of Appeal, 25 November 2025, Amgen v Sanofi, Court of Appeal, 25 November 2025, NJOY v VMR, Court of Appeal, 29 December 2025, Rematec v Europe Forestry, Court of Appeal, 17 February 2026, Messerle v Sabert, Vienna Local Division, 19 February 2026, Dyson v Dreame, Court of Appeal, 6 March 2026, Hefei Xinhu v Grundfos, Court of Appeal, 27 May 2026, Kodak v Fujifilm, Court of Appeal, 2 June 2026, Fujifilm v Kodak, Court of Appeal, 13 July 2026.

Prepared by Dhenne Avocats from the official decision, consulted on 10 October 2026. The database is updated every week, on Friday. Only the official text is authoritative.