According to Art. 123(2) EPC the European patent application or the European patent may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed. The revision of the EPC has introduced a purely editorial change to the wording of Art. 123(2) EPC to bring it into line with Art. 123(1) EPC.
The underlying idea of Art. 123(2) EPC is that an applicant should not be allowed to improve his position by adding subject-matter not disclosed in the application as filed, which would give him an unwarranted advantage and could be damaging to the legal security of third parties relying on the content of the original application (see G 1/93, OJ 1994, 541).
The "gold standard" (G 2/10, OJ 2012, 376) for assessing compliance with Art. 123(2) EPC is the following; any amendment to the parts of a European patent application or of a European patent relating to the disclosure (the description, claims and drawings) is subject to the mandatory prohibition on extension laid down in Art. 123(2) EPC and can therefore, irrespective of the context of the amendment made, only be made within the limits of what a skilled person would derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing, from the whole of these documents as filed (G 3/89, OJ 1993,117; G 11/91, OJ 1993, 125). See also in this chapter II.E.1.2. "Standard for assessing compliance with Article 123(2) EPC" further below.
The Enlarged Board has stressed the importance of applying a uniform concept of disclosure (with reference to Art. 54, 87 and 123 EPC; see G 2/10, point 4.6 of the Reasons, citing G 1/03, OJ 2012, 436, point 2.2.2 of the Reasons).
In the case of divisional applications, the same principles are to be applied for determining whether subject-matter extends beyond the content of the earlier application as filed (, OJ 2008, 271, point 5.1 of the Reasons). The decisions dealing with such cases are also reported in this chapter.