By order of 21 September 2026, the Court of Appeal of the Unified Patent Court dismissed Sidel’s appeal against the Paris Central Division’s rejection of its preliminary objection. The headnote sounds unremarkable: whether an action for a declaration of non-infringement may be brought before the patent has been granted is not a question of the Court’s competence but one of the admissibility of the claims. The real significance lies in the consequence for the opt-out: such an action may deprive the proprietor of the possibility of withdrawing its patent from the UPC system.

On 3 March 2026, OMNIA sought a declaration that its labelling module does not infringe EP 4 594 194 and EP 4 624 351. Neither patent had been granted at that point; for one of them the communication under Rule 71(3) EPC – the notice of intention to grant, which as a rule leaves only formalities to be completed – had issued, for the other it followed only three weeks later. Sidel filed its opt-out applications in April; the grants were published in April and May.

The Court of Appeal construes the action according to its discernible aim: OMNIA seeks a declaration of non-infringement of the patents in their granted form, the reference to their pending status merely describing the position at the time of filing. The action is therefore one under Article 32(1)(b) UPCA, for which the UPC is competent. Whether such an action may be brought before grant goes to its admissibility – and admissibility is not among the objections exhaustively listed in Rule 19 RoP, which the defendant may raise in advance by way of a preliminary objection. That question is left to the further proceedings, the Court itself indicating that Rules 61 and 63 RoP may require a granted patent for an action for a declaration of non-infringement.

For the opt-out, however, the Court draws a clear conclusion. Under Article 83(3) UPCA, withdrawal is possible only so long as no action has yet been brought before the Court, and “action” covers each of the types of action listed in Article 32 UPCA. The declaration action of March preceded the opt-out applications, which are therefore ineffective. Sidel’s objection that it was thereby deprived of its right to opt out is not accepted – all the more so since Article 83(3) UPCA expressly affords the opt-out to applicants as well.

For practice, this means that anyone wishing to keep a patent outside the UPC system should declare the opt-out while the application is still pending rather than waiting for grant. Conversely, competitors have in the early declaration action a means of securing the UPC’s competence before the proprietor can react. It remains open, however, whether the blocking effect persists where the action is later dismissed as premature and thus inadmissible. The wording of Article 83(3) UPCA rather suggests that it does; the point has not been decided.

In short: whoever wants the opt-out should not wait should apply for it as early as possible.