In G 1/06 (OJ 2008, 307) the Enlarged Board ruled that Art. 76 EPC 1973 also applied to divisionals from divisionals, because – if not specifically provided otherwise – divisionals must be treated just like any other application. Therefore a divisional (of whatever generation) could be the "earlier application" within the meaning of Art. 76(1) EPC 1973 for a further divisional. In the case of a sequence of applications consisting of a root (originating) application followed by divisional applications, each divided from its predecessor, it was a necessary and sufficient condition for a divisional application of that sequence to comply with Art. 76(1) EPC 1973, second sentence, that anything disclosed in that divisional application be directly and unambiguously derivable from what is disclosed in each of the preceding applications as filed (see G 1/06, headnote). Content which had been omitted on filing a member higher up the sequence could not be re-introduced into that member or in divisional applications lower down the sequence from it. Conversely, content which has been added on filing of a divisional application a sequence higher up could not be claimed in a divisional application down the sequence because according to Art. 76(1) EPC such added matter did not benefit from the filing date of the root application in which it was not disclosed (see G 1/06, point 11.2 of the Reasons).
In T 2175/09 the appellant accepted that Articles 76(1) and 100(c) EPC 1973 prohibited adding subject-matter beyond the content of the immediately preceding application from which a divisional application was derived, and that it was the purpose of these articles to prohibit extending the subject-matter beyond the root application as filed. However, the appellant argued that an infringement of Art. 76(1) EPC 1973 in the case of an intermediate higher-generation divisional application (here the grandparent application) did not constitute a ground for opposition under Art. 100(c) EPC 1973. The board held that Art. 100(c) EPC 1973 gave the public the possibility of opposing a patent on the ground that its subject-matter extended beyond the content of the earlier application as filed if an infringement of Art. 76(1) EPC 1973 had been overlooked in examination proceedings. This also applied in the particular case of an infringement of Art. 76(1) EPC 1973 in an intermediate higher-generation divisional application. The grandparent application too is "the earlier application" within the meaning of Art. 100(c) EPC.