A claim may be limited by inclusion of additional features, provided the resulting combination was directly and unambiguously disclosed in the application as originally filed in an explicit or implicit manner and does not relate to an invention which was not searched (Guidelines H‑V, 3.2 – November 2018 version).

R. 137(5) EPC states: "Amended claims may not relate to unsearched subject-matter which does not combine with the originally claimed invention or group of inventions to form a single general inventive concept. Nor may they relate to subject-matter not searched in accordance with Rule 62a or Rule 63".