In decision G 1/25 of 3 September 2026, the EPO’s Enlarged Board of Appeal ruled on the adaptation of the description: when claims are amended, the description only has to be brought into line if the amendment creates an inconsistency that leads to a breach of a specific EPC requirement. The EPC does not require “formal concordance” for its own sake, and embodiments that fall outside the claims do not, on their own, create an inconsistency. This matters to every applicant prosecuting European patents, including Euro-PCT applications coming from Latin America and smaller portfolios where each round of amendments has a cost.
Key takeaways
- G 1/25 answers three questions referred by Technical Board 3.3.02 in T 697/22 (“Hydroponics”, Knauf Insulation v Rockwool).
- Adaptation is required only if, because of the inconsistency, Articles 52 to 57, 76(1), 83, 84, 123(2) or 123(3) EPC are not complied with.
- An inconsistency exists only where the skilled person, reading the claim with the description, is left in real doubt about its meaning.
- The same test applies in examination and in opposition.
- Until the EPO amends its Guidelines, expect examiners to raise more reasoned, case-specific objections rather than routine requests to delete passages.
What did the Enlarged Board decide in G 1/25?
The referral came from an opposition appeal concerning European patent EP 2 124 521. The Board asked whether the description must be adapted when amended claims become inconsistent with it, on what legal basis, and whether the answer differs in examination. The decision of 3 September 2026 answers as follows:
| Question | Answer | Practical meaning |
|---|---|---|
| 1. Must the description be adapted after claim amendments in opposition? | Yes, but only if the inconsistency causes non-compliance with the EPC | No adaptation “for the sake of formal concordance” |
| 2. Which EPC provision requires it? | No single provision: the legal basis is whichever requirement is breached because of the inconsistency | The examiner must identify the provision at stake |
| 3. Is examination different? | No | Same test before grant and after |
The Board rejected the line of case law, led by T 56/21, which treated Article 84 EPC as a “one-way street” assessed without the description. Building on G 1/24, which held that the description and drawings must always be consulted to interpret the claims, it found that an inconsistency can make a claim unclear or unsupported, or can affect novelty and inventive step if the description reflects the claim before it was narrowed.
When is there an “inconsistency” under G 1/25 adaptation of the description?
The Enlarged Board gave its own definition. There is an inconsistency where statements in the description or drawings suggest an understanding of a claim that is incompatible with its apparent meaning, and the conflict cannot readily be resolved by applying the G 1/24 interpretation principles. Two clarifications follow:
- Unclaimed examples or embodiments are not an inconsistency in themselves. They become one only if it is unclear whether they fall within the claim.
- An inconsistency with no legal effect on any EPC requirement does not need to be removed.
This marks a change from the Guidelines for Examination, F-IV, 4.3, which treat parts of the description not covered by the claims as inconsistent and ask for terms such as “preferably” or “optionally” to be removed where they make a mandatory feature look optional.
What should you change in your EP prosecution?
The EPO said, when the referral was made in August 2025, that it would continue applying the Guidelines while the case was pending and would promptly implement the Enlarged Board’s conclusions. In the meantime, a sensible approach is:
- When an examiner asks for adaptation, ask which EPC requirement is affected and why the passage creates real doubt about the claim.
- Do not delete embodiments by default. Removing subject-matter can cost you fallback positions and can raise Article 123(2) issues.
- Do fix passages that contradict a limitation you added for novelty or inventive step: G 1/25 gives the example of a description still teaching the claim as it was before an amendment made to overcome an obviousness objection.
- Remember that statements made to the EPO to justify keeping a passage form part of the file history.
- In opposition appeals, prepare the adapted description before the oral proceedings. The Board noted that it is almost always finalised there.
What this means for your business
For Euro-PCT applications filed from Latin America, where the description was drafted for a home office and may contain many alternatives, G 1/25 reduces the risk of having to strip it to match narrowed European claims. For SMEs and universities, fewer automatic adaptation rounds can mean fewer communications before grant. The benefit is not automatic, though: an examiner may still object, now with a more reasoned argument, and the response has to engage with it. Our patent prosecution team for European and Euro-PCT applications can review pending files where an adaptation request is open.
Where applicants could get G 1/25 wrong
- Reading it as “no adaptation ever”. Adaptation is still required where an inconsistency breaches the EPC.
- Leaving contradictory passages in place after narrowing the claims for patentability. These are the passages G 1/25 says must go.
- Over-arguing in writing. Explanations of why a passage can stay may be used later in national courts or before the Unified Patent Court.
- Handling each file separately. Applicants with several families pending benefit from one consistent position across examination, opposition and validation.
Frequently asked questions
Does G 1/25 abolish the adaptation of the description at the EPO?
No. G 1/25 confirms that the description must be adapted when a claim amendment introduces an inconsistency that leads to non-compliance with Articles 52 to 57, 76(1), 83, 84, 123(2) or 123(3) EPC. What it rules out is adaptation merely for formal concordance, and the idea that unclaimed embodiments are inconsistent in themselves.
Does G 1/25 apply to applications in examination?
Yes. The Enlarged Board answered the third referred question in the negative: the interpretative role of the description does not depend on the procedural stage, so the same test applies to amended claims in examination and examination appeals as in opposition and opposition appeals.
Has the EPO changed its Guidelines after G 1/25?
On the date of the decision, the Guidelines for Examination (F-IV, 4.3) still reflected the earlier practice. The EPO had said in August 2025 that it would promptly implement the Enlarged Board’s conclusions, so applicants should watch for an amendment to the Guidelines or a notice in the Official Journal.
Can IP Global Guard review my pending European applications?
Yes. We review pending European and Euro-PCT files where the description has been or may be challenged, and coordinate responses with European patent attorneys, keeping one strategy across your portfolio in Europe, Latin America and Africa from a single point of contact.
Talk to us about your pending EP files
G 1/25 gives applicants more room, but only to those who use it with care. IP Global Guard, the IP services line of META Channel Corporation Limited, coordinates patent prosecution across more than 25 jurisdictions in Europe, Latin America and Africa with one strategy and one billing relationship; see our international coverage.
Send us the application numbers of files with an open communication on the description, or where amendments are coming. We will tell you where adaptation is really needed and where it can be resisted. Contact our patent team.
This article is general information, not legal advice, and reflects the situation on its publication date.
