According to Art. 123(3) EPC the European patent may not be amended in such a way as to extend the protection it confers. This refers to the patent as a whole. The wording of Art. 123(3) EPC 1973 had referred only to the claims of the patent; however, already under the EPC 1973, the boards had held that amendments to the description and the drawings could also extend the protection conferred within the meaning of Art. 123(3) EPC 1973 (see T 1149/97, OJ 2000, 259).

Art. 123(2) EPC and Art. 123(3) EPC are mutually independent of each other (G 1/93, OJ 1994, 541); the same is true for Art. 76(1) EPC and Art. 123(3) EPC (T 1736/09).