Do Rule 56 EPC (missing parts) and Rule 56a EPC (erroneously filed application documents) apply to divisional applications?

Introduction

The Patent Law Treaty (PLT) was adopted in 2000. The Patent Law Treaty (PLT) was adopted on 01.06.2000 at a Diplomatic Conference in Geneva and entered into force on 28.04.2005. Currently (August 2022), there are 43 member States. See www.wipo.int/en/web/treaties/ip/plt/index (accessed 01.05.2026). Although open to intergovernmental organization (Art. 20(3) PLT) and despite the European Patent Organisation wrote down its wish to become a party to the PLT (Document MR/2/00 of the Travaux Préparatoires to the EPC 2000), the Organisation never ratified the PLT. The aim of this Treaty is “to harmonise and streamline” formal procedures relating to national and regional patent applications and maintenance of patents. During the Revision of the European Patent Convention (EPC 2000), The revised European Patent Convention (also referred to as “EPC 2000”) was adopted on 29.11.2000 at a Diplomatic Conference in Munich and entered into force on 13.12.2007. See www.epo.org/en/legal/epc (accessed 01.05.2026). the key features of the PLT were implemented into the EPC. This included, amongst others, simplifying the requirements for the accordance of a date of filing, Art. 5(1) PLT; Rule 40 EPC. and the filing of a European patent application by reference, Art. 5(7) PLT; Rule 40(1)(c) EPC. as well as – in Rule 56 EPC – the filing of missing parts of the description or missing drawings. Art. 5(6) PLT; Rule 56 EPC. Note that Rule 56 EPC is similar to, but slightly different from, the provisions with respect to missing parts and elements in PCT Rule 20, in particular PCT Rule 20.3 (missing elements), PCT Rule 20.5 (missing parts), PCT Rule 20.6 (confirmation of incorporation by reference of elements and parts) and PCT Rule 20.7 (time Limit). E.g., Rule 56 EPC does not provide for missing claims or parts thereof.

The reason for the introduction of Rule 56a in the EPC was the earlier introduction of PCT Rule 20.5_bis_ into the PCT on 1 July 2020. PCT Rule 20.5bis was adopted by the PCT Union Assembly on 09.10.2019 and entered into force on 01.07.2020. See www.wipo.int/meetings/en/details.jsp?meeting_id=52258 (accessed 01.05.2026). The Rule lays down a procedure for the correction of “erroneously filed” application documents. The Rule allows an applicant of an application – under limited circumstances – to replace erroneously filed claims and/or the description of the application (or parts thereof) or erroneously filed drawings with the equivalent “correct” version of the claims, the description or the drawings (or a part thereof) as contained in the priority application. See e.g., documents PCT/WG/12/9 (29.04.2019) and PCT/WG/12/24 (14.06.2019) of the PCT Working Group.

The introduction of PCT Rule 20.5bis was aimed at aligning the practices of receiving Offices and designated/elected Offices in the special case where an applicant had erroneously filed a wrong element or part of the international application. An “element” is “all of the claims or all of the description”. A “part” is “a part of the description, part of the claims, part or all of the drawings”. See PCT Rule 20.5(a) or 20.5bis(a). PCT Rule 20.5_bis_ had to be introduced because the EPO as receiving Office was of the opinion that, under PCT Rules 4.18, 20.5 and 20.6, the practice of allowing the inclusion of a new complete set of claims or a new complete description where the element concerned had been erroneously filed, is not permissible. Also see the “Practical Advice” in PCT Newsletter 07-08/2015 “Diverging practices of receiving Offices regarding the incorporation of missing parts”. Also see the decision of the legal board of appeal (EPO) J 27/10, catchword 1 in relation to the same problem with Rule 56 EPC.

As PCT Rule 20.5_bis_ was incompatible with the practice under the EPC, the EPO initially notified the International Bureau of WIPO of its incompatibility. The EPO as receiving Office and designated/elected Office did not apply PCT Rules 20.5bis(a)(ii) and (d) as of 01.07.2020. This reservation was withdrawn when Rule 56a EPC entered into force on 01.11.2022. Also see Official Notices (PCT Gazette) issued by WIPO (20.01.2020).

The introduction of Rule 56a EPC was aimed at aligning the practice under the EPC with PCT Rule 20.5_bis_. “Notice from the EPO dated 23 June 2022 concerning the correction of erroneous filings in proceedings before the EPO”, OJ EPO 2022 A71, in particular items 1-4. Rule 56a EPC is structured in an analogous way as Rule 56 EPC but has additional provisions. In particular Rule 56a EPC also covers erroneously filed claims, as well as same-day corrections.

In an article published in epi Information, the current authors described the Rule 56a EPC in detail as well as the simultaneous amendment of Rule 56 EPC. Cees Mulder and Roel van Woudenberg: “New Rule 56a and amendments to Rule 56 EPC – Background, requirements and consequences” in epi Information 03|2022 pp.10-17. In a subsequent article in epi Information, the authors discussed the shortcomings of Rule 56 and Rule 56a EPC and other related Rules to better accommodate the filing of missing parts and the correction of erroneously filed application documents into the framework of EPC. The latter article included a comprehensive proposal to amend Rules 56, 56a, 28, 45 and 159 EPC to resolve the problems. Cees Mulder and Roel van Woudenberg: “Rule 56a EPC and time travel” in epi Information 03|2023 pp.10-21.

The Guidelines indicate that the EPO seems to consider that Rule 56 and Rule 56a EPC also apply to divisional applications The authors acknowledge that Rules 56 and 56a EPC could theoretically be used for divisional applications when these are filed shortly after the parent application, provided that the missing parts or correct parts are filed within two months after the date of filing of the parent (which is the filing date of the divisional application Art. 76(1) EPC). However, such situation is unlikely to occur in practice and is so exceptional that it is not necessary to address this in the Guidelines. The authors also acknowledge that Rules 56 and 56a EPC could be used if the EPO were to issue an invitation to do so; however, the cited paragraph from the Guidelines does not mentions this scenario., and may be interpreted that the two-month time limit would run from the date of receipt rather than the date of filing: See GL/EPO (2026) A-IV 1.1, 3^rd paragraph. This addition was made for the first time in the 2023 edition of the Guidelines.

Where the applicant inserts missing parts of the description and/or missing drawings under Rule 56 (see A-II, 5) or corrects erroneously filed parts under Rule 56a (see A-II, 6) after the divisional application’s date of receipt, the requirements of Rule 36(1) may no longer be fulfilled (see A-IV, 1.1.1). It cannot be understood how “the requirements of Rule 36(1) may no longer be fulfilled” could apply, as this would only be the case if the divisional application were to be re-dated (e.g., under Rule 56(2) or Rule 56a(3) EPC), but such re-dating is not possible for a divisional application in view of Art. 76(1) EPC, see also GL/EPO (2026) A-IV 1.2.1, 3^rd paragraph. Furthermore, GL/EPO (2026) C-IX 1.4 provides that “The divisional application cannot be converted into an independent application taking its own date of filing.” If the divisional application claims priority, the date of receipt does not change if the missing parts or the correct application documents are completely contained in the earlier application whose priority is claimed (Art. 88(1)).

This article examines this suggestion and concludes that the current wording of Rule 56 and Rule 56a EPC does – in all practical cases – not allow their application to divisional applications. If such applicability is desired, in particular where the missing parts or the corrected parts replacing erroneously filed parts are completely contained in the immediate parent application, a new Rule 56b should be inserted into the EPC to enable the submission of missing parts or corrected application documents after the filing of a divisional application. The wording of such a new Rule is included in an annex.

Why this article?

Rules 56 and 56a EPC are rarely used in practice. Unconfirmed information suggests that these Rules has been applied fewer than ten times in the last five years. During the same period, however, they have regularly been the subject of questions in the European Qualifying Examination (EQE). Rules 56 and 56a EPC (or the corresponding PCT Rules 20.5 and 20.5_bis_, in combination with PCT Rules 20.6, 20.7 and 4.18) have been the subject of more than 10 questions in Paper D1, in Paper D2, and even in the Pre-Examination of the EQE.

On top of that, the first question of the very last D1 Paper (2026) concerned the use of Rule 56a EPC in a situation where a divisional application was derived from a Euro-PCT application. See www.epo.org/en/learning/eqe-epac/european-qualifying-examination-eqe/compendium/paper-d (accessed 01.05.2026). The D committee seems to have assumed that Rule 56a EPC applied to this divisional application, based on the Guidelines (see above). See GL/EPO (2026) A-IV 1.1, 3^rd paragraph. The authors have informed the committee that they are of the opinion that this interpretation lacks a legal basis and is too uncertain to form the basis of an EQE question.

These are the reasons to investigate the applicability of Rules 56 and 56a EPC to divisional applications in more detail. To this end, we will examine the legislation and, on that basis, formulate how a Rule similar to Rule 56 and 56a EPC can be incorporated into the EPC that applies to divisional applications.

In the first part of this article, we focus on Rule 56a EPC. We will show the shortcomings of current Rule 56a EPC when applied to divisional applications, and based on this, formulate a new Rule 56b EPC. Later on, we will show that the requirements for filing missing parts of Rule 56 EPC can simply be incorporated into the new Rule 56b EPC.

Can Rule 56a EPC be applied to divisional applications?

Paragraphs 3 and 4 constitute the essential parts of Rule 56a EPC and read as follows: Note that the term ‘earlier application’ in Rule 56(3) and Rule 56a(4) EPC is formulated as follows: ‘claims priority from an earlier application’. Hence, the ‘earlier application’ unambiguously refers to the priority application. It would be incorrect to regard a parent application of a divisional application as the ‘earlier application’ within the meaning of those Rules, despite the fact that that term is used in other contexts for such a parent application.

(3) If correct application documents or parts referred to in paragraph 1 are filed later than the date of filing, but within two months of the date of filing For a divisional application, the date of filing is the date of filing of the parent application, see Art. 76(1) EPC and GL/EPO (2026) A-IV 1.2.1. Also refer to GL/EPO (2026) C-IX 1.1 and 1.4. or, if a communication is issued under paragraph 1 or under Rule 56, paragraph 1, within two months of that communication, the application shall be re-dated to the date on which the correct application documents or parts were filed. The correct application documents or parts shall be included in the application and the erroneously filed application documents or parts shall be deemed not to have been filed. The European Patent Office shall inform the applicant accordingly.

(4) If the correct application documents or parts are filed within the period under paragraph 3, and the application claims priority of an earlier application on the date on which the requirements laid down in Rule 40, paragraph 1, were fulfilled, the date of filing shall, provided that the correct application documents or parts are completely contained in the earlier application, remain the date on which the requirements laid down in Rule 40, paragraph 1, were fulfilled, where the applicant so requests and files, within the period under paragraph 3:

(a) a copy of the earlier application, unless such copy is available to the European Patent Office under Rule 53, paragraph 2;

(b) where the earlier application is not in an official language of the European Patent Office, a translation thereof in one of these languages, unless such copy is available to the European Patent Office under Rule 53, paragraph 3;

and

(c) an indication as to where the correct application documents or parts are completely contained in the earlier application and, where applicable, in the translation thereof.

If these requirements are fulfilled, the correct application documents or parts shall be included in the application and the erroneously filed application documents or parts shall remain in the application.

Rule 56a(3) EPC and regular European patent applications

For Euro-direct or Euro-PCT applications, Rule 56a(3) EPC allows an applicant to correct of own volition the description, claims and drawings (or parts thereof) after the date of filing if they were filed “erroneously”. The erroneously filed application documents (or parts) will be deemed not to have been filed, and the correct documents will be added to the application. Consequently, the date of filing of the application is shifted to the date of receipt of the correct application documents (or parts). The applicant should be aware that a change of the date of filing may result in the loss of the right to priority.

Can Rule 56a(3) EPC be applied to divisional applications?

As one can see above, Rule 56a(3) EPC refers to “the date of filing”. For any divisional application, the ‘date of filing’ is the date of filing of the (root) parent application, Art. 76(1) EPC: A European divisional application shall be filed directly with the European Patent Office in accordance with the Implementing Regulations. It may be filed only in respect of subject-matter which does not extend beyond the content of the earlier application as filed; in so far as this requirement is complied with, the divisional application shall be deemed to have been filed on the date of filing of the earlier application and shall enjoy any right of priority. and not e.g., the date on which the applicant filed the divisional application or the date on which the EPO received the divisional application. So, if the date of filing of the divisional is the date of filing of the parent application, then the period “within two months of the date of filing” is a period which normally lies in the past. Normally, divisional applications are filed during substantive examination of the parent application, e.g. for splitting of non-unitary subject-matter.> So, for this reason, Rule 56a(3) EPC as such is not applicable to divisional applications (assuming the divisional application is not filed shortly after filing the parent application).

However, in Rule 56a(3) EPC, there is a second incompatibility when filing erroneously filed application documents in divisional applications. This relates to the wording in Rule 56a(3) EPC that “the application shall be re-dated to the date on which the correct application documents or parts were filed”. A re-dating of a divisional application cannot be understood and is a violation of the essence of a divisional application, i.e., it intrinsically inherits the date of filing of the patent. See Art. 76(1) EPC. Moreover, it would be contrary to the principle that a divisional application cannot be converted into an independent application with its own date of filing. Also see GL/EPO (2026) C-IX 1.4: “The divisional application cannot be converted into an independent application taking its own date of filing.”

Conclusion: From reading the legal requirements in Rule 56a(3) EPC, it becomes clear that Rule 56a(3) with its re-dating is intrinsically incompatible with filing erroneously filed application documents or parts for divisional applications. A reformulation of Rule 56a(3) EPC to cover or to avoid re-dating of the parent application is simply impossible.

Rule 56a(4) EPC and regular European patent applications

The crux of Rule 56a(4) EPC is that the applicant is allowed to derive the correct application documents (or parts) from the priority application whereby the initial date of filing of the application is retained. Rule 56a(4) EPC: “… and the application claims priority of an earlier application on the date on which the requirements laid down in Rule 40, paragraph 1, were fulfilled, the date of filing shall, provided that the correct application documents or parts are completely contained in the earlier application…” This has to be done “within the period under paragraph 3” which we have discussed for Rule 56a(3) EPC.

In Rule 56a(4) EPC, the requirements for meeting the “completely contained” criterion have been taken over from Rule 56(3) EPC. If the correct application documents (or parts) are completely contained in the priority document, Rule 56a(4) EPC allows an applicant to maintain the initial date of filing upon adding the correct documents or parts. he priority of the earlier application must be claimed on the initial date of filing. In addition, the erroneously filed application documents (or parts) will remain in the European patent application and may only be removed by amending the application during proceedings up to grant. Any removal of erroneously filed documents (or parts) during grant proceedings is subject to the requirements for amending a European patent application under Art. 123(2) EPC. In our earlier article, we have argued that this compulsory ‘remaining’ of the erroneously filed application documents in the application is based on a misinterpretation of the similar provision in PCT Rule 20.5bis. See Cees Mulder and Roel van Woudenberg: “Rule 56a EPC and time travel” in epi Information 03|2023 pp.10-21.

See Figure 1 for a typical example of a Rule 56a(4) EPC situation for a Euro-direct application.

After filing a priority application NL1 with subject-matters A and B, EP1 is filed claiming priority from NL1, with subject-matter A and new subject-matter C, but with erroneous subject matter ‘B err’ (Figure 1). Under Rule 56a(4) EPC, the applicant can within two months of the date of filing of EP1, correct the erroneously filed subject-matter ‘B err’ by subject-matter B which is completely contained in the priority document. The subject-matter B is included in the application, and the erroneously filed subject-matter ‘B err’ remains in the application. Any removal of ‘B err’ needs to be done by amendment during grant proceedings and is subject to the extension-of-subject-matter prohibition of Art. 123(2) EPC.

Can Rule 56a(4) EPC be applied to divisional applications?

Now, let us examine the applicability of Rule 56a(4) EPC to divisional applications. As mentioned above, the core of Rule 56a(4) EPC is that the applicant is allowed derive the correct application documents (or parts) from the priority application. Rule 56a(4) EPC: “… and the application claims priority of an earlier application on the date on which the requirements laid down in Rule 40, paragraph 1, were fulfilled, the date of filing shall, provided that the correct application documents or parts are completely contained in the earlier application…“ Art. 76(1) EPC provides that a divisional application shall enjoy any right of priority. See also GL/EPO (2026) A-IV 1.2.2: “A priority claimed in the parent application also applies to the divisional application […]; it is not necessary to claim it formally a second time.”

Figures 2, 3 and 4 show examples of how current Rule 56a(4) EPC does not work for divisional applications.

After filing a priority application NL1 with subject-matters A and B, EP1 is filed claiming priority from NL1, with subject-matters A, B and new subject-matter C (Figure 2). After receipt of the partial European search report with a non-unity objection, DIV1 is filed with subject-matters A and C, followed by a further divisional DIV2 limited to subject-matter A only. Let’s assume that during the filing date examination, If we would not assume so, the two-month period from the date of filing to file these documents of own motion would already have expired. the EPO invites the applicant under Rules 56(1) and Rule 56a(1) EPC GL/EPO (2026) A-II 5.1 and A-II 6.1 indicate that the EPO will send a combined communication under Rules 56(1) and 56a(1) EPC, also if the EPO only notes that parts of the description or drawings appear to be missing or only establishes that the description, claims or drawings (or parts of them) appear to have been erroneously filed. to file missing or correct application documents or parts within two months. Then the applicant realises that DIV2 should be for subject-matter C and not for subject-matter A. Based on the priority application and referring to Rule 56a(4) EPC, Whether this should be considered an ’erroneous part (A was erroneously filed rather than C) or a ‘missing part’ (C is missing) can be debated, but it is irrelevant for the discussion: the issue arises in both Rule 56a(4) EPC and Rule 56(3) EPC. This is one of the reasons why we propose to use a single Rule 56b EPC for both missing and erroneous parts in divisional applications. the applicant indicates that that subject-matter A in DIV2 was erroneously filed and should be corrected by subject-matter C. However, subject-matter C is not in the priority document. So, this correction is not possible, while this scenario is not unlikely and shall in our view be covered by the provisions for missing and erroneous parts.

Rule 56a(4) EPC does also not work in the situation of Figure 3.

After filing a priority application NL1 with subject-matters A and B, EP1 is filed claiming priority from NL1, with subject-matters A, B and new subject-matter C (Figure 3). Later on, DIV1 is filed with subject-matters A and C, followed by a further divisional DIV2 with only subject-matter A. After receipt of an invitation under Rules 56(1) and Rule 56a(1) EPC, the applicant realises that DIV2 should be for subject-matter B and not for subject-matter A. Based on the priority application and referring to Rule 56a(4) EPC, applicant indicates that that subject-matter A in DIV2 was erroneously filed and should be corrected by subject-matter B which is in the priority application. If it were allowed to add subject-matter B to DIV2, this addition would be a violation of Article 76(1) EPC as it represents an extension of subject-matter with respect DIV1 which is the immediate parent of DIV2. Also see G 1/05 and G 1/06 and GL/EPO (2026) A-IV 1.1.2. This correction is therefore not possible, whereas current Rule 56a(4) EPC could be interpreted in such a way that it is possible. However, see Art. 164(2) EPC: “In case of conflict between the provisions of this Convention and those of the Implementing Regulations, the provisions of this Convention shall prevail.”

The non-applicability of Rule 56a(4) EPC to divisional applications becomes even ‘funnier’ (or more absurd) in the example of Figure 4.

EP1 is filed without any priority with subject-matters A, B and C (Figure 4). Later on, DIV1 is filed with subject-matters A and C, followed by a further divisional DIV2 with the intention to limit this further divisional DIV2 to subject-matter A only. After receipt of an invitation under Rules 56(1) ad Rule 56a(1) EPC, the applicant realises that DIV2 contains subject-matter ‘A err’ instead of the correct subject-matter A. The applicant may for example have used an earlier draft text of EP1, different from the final text of EP1, when preparing the application documents for DIV2. Now the applicant cannot apply Rule 56a(4) EPC because EP1 does not claim priority. So, this correction is not possible, while this scenario is not at all unlikely and shall in our view be covered by the provisions for missing and erroneous parts. In all situations described in Figures 2-4, the restriction that any correction has to be done “within the period under paragraph 3” which is “within two months of the date of filing” has been disregarded as that situation will in practice not occur. In order to ensure that Rules 56a(4) and 56(3) EPC would still apply, the authors have included an artificial invitation based on Rules 56(1) and 56a(1) EPC, even though it seems unlikely that the EPO would issue such an invitation in these cases.

Conclusion: From reading the legal requirements in current Rule 56a(4) EPC and in view of the given examples, it becomes clear that for divisional applications, the priority application is not the proper earlier application for incorporating correct application documents (or parts thereof).

In the next paragraph, we will explore what would be the proper application for incorporation of the correct (or missing) application documents or parts thereof.

Correcting erroneously filed application documents in the case of divisional applications requires new legislation

A suitable manner to allow the filing of erroneously filed application documents (or parts) in a divisional application could be that the correction is taken from the application from which the divisional application is derived, i.e. the immediate parent application. This is the only way to avoid conflict with extension of subject-matter under Article 76(1) EPC. Also see G 1/05 and G 1/06 and GL/EPO (2026) A-IV 1.1.2. Moreover, this would address the most likely cause as to why erroneously filed application documents were filed.

To substantiate the latter comment, we return to the erroneously filed application documents for a Euro-direct application and incorporation of correct documents. In that case, the likely situation is that the European patent application EP1 contains the same subject-matter as the priority application NL1 plus some additional subject-matter. Only the same subject-matter from the priority application NL1 (or part thereof), can be incorporated under Rule 56a(4) EPC. This subject-matter is also the only subject-matter for which it was clearly indicated that it was intended to be filed as part of EP1 (first element of evidence), provided that priority was claimed on the (initial) date of filing (second element of evidence). The presence of these two pieces of evidence is in fact the reason why incorporation is allowed, despite the time travel aspect. Rule 56a(4) EPC thus acknowledges the direct link between a Euro-direct application and its associated priority application.

Let us now consider a divisional application DIV1, derived from patent application EP1. The divisional application DIV1 may have the same or less subject-matter as the immediate parent application (first element of evidence), so it is appropriate if that this content can be incorporated. Furthermore, the parent application must be identified when filing the divisional application (second element of evidence). A new Rule must therefore acknowledge the direct link between a divisional application and its parent application.

Conclusion: in order to enable correction of erroneously filed application documents in a divisional application, the “priority application” (from which under current Rule 56a(4) EPC the correction is taken) should be replaced by the “application from which the divisional application derives”, hence the immediate parent application. If that is done, the period of “two months of the date of filing” should be replaced with a period of “two months of the date of receipt of the divisional application”.

This would lead to the following formulation of a new Rule 56b(2) which is equivalent to Rule 56a(4) EPC, but now applied to the situation of divisional applications (emphasis added):

If correct application documents or parts referred to in paragraph 1 are filed within two months of the date of receipt of the divisional application, or, if a communication is issued under paragraph 1, within two months of that communication, and the correct application documents or parts are completely contained in the application from which the divisional application derives …

Rule 56b(1) EPC would simply be the equivalent of Rule 56a(1) EPC referring to the (rather unlikely) case that the EPO discovers that erroneously filed documents or parts have been filed in the divisional application with respect to the parent application.

There would be no equivalent to Rule 56a(3) EPC (which providers for a re-date to the date on which the correct application documents or parts were filed), since the date of filing of a divisional application cannot be changed, nor can a divisional application be converted into an independent application taking its own date of filing. GL/EPO (2026) C-IX 1.4.

New Rule 56b(2) EPC shows a clear relationship between the divisional application and its (direct) parent application. The EPO has all the documents relating to the parent application in the language of the proceedings, so items (a) and (b) of current Rule 56a(4) EPC need not be included in Rule 56b(2) EPC. In particular, it is sufficient if the applicant when filing correct application documents (or parts) indicates as to where the correct application documents or parts are completely contained in the application from which the divisional application derives.

Rule 56a(4) EPC stipulates that the erroneously filed application documents remain in the application. In the earlier article, it was argued that this requirement is a misconception based on a requirement in PCT Rule 20.5_bis_. Cees Mulder and Roel van Woudenberg: “Rule 56a EPC and time travel” in epi Information 03|2023 pp.10-21. The reason for PCT Rule 20.5bis(d) to keep both versions (erroneous and corrected) in the international application lies in the incompatibility with some national law/reservations of designated Offices: it aims to allow, after incorporation by the receiving Office, to proceed with the relevant version in the national phases of Offices without and with reservations. In the EPC, there is no such “phase”, there are no “reservations” and, hence, there is no need for keeping two versions of the application documents ‘active’. Therefore, Rule 56a(4) EPC should have stated that the corrected parts replace the erroneously filed parts, similar to Rule 56a(3) EPC, so that there is also no need for any amendment to delete the erroneous part in Rule 56a(4) EPC, as there is no such requirement in Rule 56a(3) EPC. Moreover, if erroneously field application documents remain in the divisional application, while the parent application does not comprise those same parts, they would need to be amended out anyhow, Art.76(1) EPC, GL/EPO (2026) C-IX 1.4. whereas erroneously filed parts in a Euro-direct application can in principle be retained. As both the erroneously filed parts as well as the correct parts are considered part of the application as filed under current Rule 56a(4) EPC, the applicant can still choose to amend to the one or the other even at a late stage, as long as Rule 137(5) EPC is satisfied.

This then establishes that in Rule 56b(2) EPC (emphasis added):

… the correct application documents or parts shall be included in the divisional application and the erroneously filed application documents or parts thereof shall be deemed not to have been filed.

For completeness, Rule 56b(3) EPC is the equivalent of Rule 56a(5)/(6) EPC where the filing of correct application document is deemed not to have been made. Rule 56b(4) EPC is the equivalent of Rule 56a(6) EPC and relates to the withdrawal of the correct application documents. In addition, Rule 56b(5) EPC is the equivalent of Rule 56a(8) EPC and applies to situations where the EPO has already begun to draw up the search report before the correct application document have been filed. Also see: “Draft Rule 56a EPC regarding correction of erroneous filings” SACEPO WPR 5/20 (21.02.2020): item 21.

Examples of filing missing parts or correcting erroneously filed application documents in divisional applications with proposed new Rule 56b EPC

Figures 5 and 6 show that with new Rule 56b EPC, we can now correct erroneously filed application documents in divisional applications.

After filing a priority application NL1 with subject-matters A and B, EP1 is filed claiming priority from NL1, with subject-matters A, B and new subject-matter C (Figure 5). Later on, DIV1 is filed with subject-matters A and C, followed by a further divisional DIV2 but with erroneous subject matter ‘A err’. Under Rule 56b(2) EPC, the applicant can within two months of filing the divisional application DIV2 (or within two months from a communication under Rules 56(1), 56a(1) and 56b(2)), correct the erroneously filed subject-matter ‘A err’ by subject-matter A which is completely contained in divisional application DIV1, i.e. the immediate patent (divisional) application. The subject-matter A is included in the divisional application DIV2, and the erroneously filed subject-matter ‘A err’ is deemed not to have been filed.

After filing a priority application NL1 with subject-matters A and B, EP1 is filed claiming priority from NL1, with subject-matters A, B and new subject-matter C (Figure 6). Later on, DIV1 is filed with subject-matters A and C, followed by a further divisional DIV2 but with subject-matter A. Then the applicant realises that DIV2 should deal with subject-matter C instead of A. Under Rule 56b(2) EPC, the applicant can within two months of filing the divisional application DIV2 (or within two months from a communication under Rules 56(1), 56a(1) and 56b(2) EPC), correct the erroneously filed subject-matter A by subject-matter C which is completely contained in divisional application DIV1, i.e. the immediate patent (divisional) application. Subject-matter C is included in the divisional application DIV2, and the erroneously filed subject-matter A is deemed not to have been filed.

EP1 is filed without any priority with subject-matters A, B and C (Figure 7). Later on, DIV1 is filed with subject-matters A and C, followed by a further divisional DIV2 with the intention to limit this further divisional DIV2 to subject-matter A only. Under Rule 56b(2) EPC, the applicant can within two months of filing the divisional application DIV2 (or within two months from a communication under Rules 56(1), 56a(1) and 56b(2) EPC), when realising that DIV2 contains subject-matter ‘A err’ instead of the correct subject-matter A. correct the erroneously filed subject-matter ‘A err’ by subject-matter A which is completely contained in divisional application DIV1, i.e. the immediate patent (divisional) application. Subject-matter A is included in the divisional application DIV2, and the erroneously filed subject-matter ‘A err’ is deemed not to have been filed.

In the examples shown in Figures 5, 6 and 7, there is no violation of Article 76(1) EPC in relation to extension of subject-matter beyond the content of the earlier application as filed.

Incorporating an equivalent of Rule 56 EPC into the new Rule 56b EPC

As already mentioned in this article, in the above we have primarily focused on the incompatibility of Rule 56a EPC and divisional applications. The same applies to Rule 56 EPC dealing with filing missing of parts of the description and or filing missing drawings. As we are formulating a new Rule 56b EPC, it is straightforward to incorporate both the filing of missing parts and the correction of erroneously filed application documents into the new Rule 56b EPC. Similar to Rule 56a(3) EPC, the re-dating as described in Rule 56(2) EPC is intrinsically incompatible with divisional applications.

The current Rule 56 EPC does not allow the filing of missing claims. This omission was discussed in our previous paper. Cees Mulder and Roel van Woudenberg: “Rule 56a EPC and time travel” in epi Information 03|2023 pp.10-21. Although the preparatory documents advocated the alignment of the EPC with the provisions of the PCT (rather than just with the PLT), Document CA 4/21 (President of the EPO; 07.09.2021) items 6, 14 and 34 for Rule 56a EPC; CA 4/21 items 17 and 35 for the amendment to Rule 56 EPC. and despite the importance of claims being part of the application as filed, Art. 123(2) EPC, Art. 54(3) EPC, Rule 139 EPC, Art. 14(2), second sentence, EPC and Art. 66 EPC. the possibility of filing of missing claims under Rule 56 EPC was not incorporated when amending Rule 56 EPC. The argument that Rule 40 EPC does not require the presence of claims and that Rule 56 EPC ‘therefore’ need not permit the filing of missing parts of the claims, is refuted by the fact that Rule 40 EPC also does not refer to drawings, whereas Rule 56 EPC nevertheless permits the filing of missing drawings.

In the new Rule 56b EPC, we have included the filing of missing claims or parts thereof:

(1) If the examination under Article 90, paragraph 1, of a divisional application reveals that parts of the description appear to be missing, or claims or drawings or parts of those application documents appear to be missing …

Please note that in an Annex, a complete formulation of new Rule 56b EPC for divisional applications is presented including a combination of Rule 56 and 56a EPC. In particular:

• Rule 56b(1) EPC is the equivalent of Rule 56(1) and Rule 56a(1) EPC (invitation);
• Rule 56b(2) EPC is the equivalent of Rule 56(3) and Rule 56a(4) EPC (incorporation);
• Rule 56b(3) EPC is the equivalent of Rule 56(4)/(5) and Rule 56a(5)/(6) EPC (no effect);
• Rule 56b(4) EPC is the equivalent of Rule 56(6) and Rule 56a(6) EPC (withdrawal);
• Rule 56b(5) EPC is the equivalent of Rule 56a(8) EPC (further search fee).

A provision of inviting he applicant to pay a further search fee was not included in Rule 56 EPC because under that Rule, missing parts of the claims could not be filed. Under new Rule 56b(5) the possibility of asking for a further search fee also when filing missing claims or parts thereof was included.

Conclusion

This article demonstrates that Rules 56 and 56a EPC cannot be applied to divisional applications without substantial modifications. To remedy this, a proposal is presented for inserting a new rule 56b into the EPC covering missing parts as well as erroneously filed application documents in divisional applications. In an Annex, a complete formulation of new Rule 56b EPC for divisional applications is presented.

ANNEX 1 – Proposal for new Rule 56b EPC

Rule 56b EPC – Missing parts of the description, missing claims or missing drawings and erroneously filed application documents or parts in divisional applications

(1)

If the examination under Article 90, paragraph 1, of a divisional application reveals that

parts of the description appear to be missing, or claims or drawings or parts of those application documents appear to be missing, or

the description, claims or drawings, or parts of those application documents appear to have been erroneously filed,

the European Patent Office shall invite the applicant to file the missing or correct application documents or parts within two months.

The applicant may not invoke the omission of such a communication.

(2)

If missing or correct application documents or parts referred to in paragraph 1 are filed within two months of the date of receipt of the divisional application, or, if a communication is issued under paragraph 1, within two months of that communication, and

1. provided that the missing or correct application documents or parts are completely contained in the application from which the divisional application derives, and
2. where the applicant so requests and files an indication as to where the missing or correct application documents or parts are completely contained in the application from which the divisional application derives, and, where applicable, in the translation thereof,

the missing or correct application documents or parts shall be included in the divisional application and, where applicable, the erroneously filed application documents or parts thereof shall be deemed not to have been filed.

The European Patent Office shall inform the applicant accordingly.

(3)

If the applicant:

a. fails to file the missing or correct application documents or parts within the period under paragraph 1 or 2,

or

b. withdraws under paragraph 4 any missing or correct application documents or parts filed under paragraph 2,

or

c. fails to comply with paragraph 2(ii),

any filing of the missing or correct application documents or parts shall be deemed not to have been made and, where applicable, the erroneously filed application documents or parts shall remain in the divisional application or be restored to the divisional application.

The European Patent Office shall inform the applicant accordingly.

(4)

Within one month of the notification referred to in paragraph 2, the applicant may withdraw the missing or correct application documents or parts filed.

The European Patent Office shall inform the applicant accordingly.

(5)

If the applicant files missing or correct application documents or parts under paragraph 2 after the European Patent Office has begun to draw up the search report, the European Patent Office shall, where applicable, invite the applicant to pay a further search fee within one month.

If the search fee is not paid in due time, the divisional application shall be deemed to be withdrawn.

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