A decision remitting a case to the opposition division with the order to maintain a patent on the basis of amended claims is binding in the sense that neither the wording nor the patentability of those claims can be challenged again in subsequent EPO proceedings (T 843/91 date: 1993-08-05, OJ 1994, 832). The decision on the claims' patentability remains final even where the facts have changed (T 27/94). When the first board of appeal delivers its decision, the content and the text of the patent claims become res judicata and can no longer be amended in proceedings before the EPO (T 113/92). Only objections to the amendments made to the description by the opposition division can be examined on appeal (T 1063/92).

Remittal for the description to be amended does not render it possible for an opponent to challenge substantive patentability again by appealing the opposition division's decision after remittal, where a final decision has been taken on this and the scope of the patent (T 1063/92). Following T 843/91 date: 1993-08-05 (OJ 1994, 832), the board in T 153/93 found that all findings of fact that were a conditio sine qua non of the finally binding parts of the decision were res judicata with the result that new facts, evidence or arguments seeking to cast doubt upon these facts could not be considered either by the opposition division or the board of appeal.

Where the board, in the decision remitting the case to the department of first instance, is silent on the question of the adaptation of the description, this does not necessarily imply that no adaptation is required, but merely that the matter was not considered or decided. The point is therefore not res judicata and so can be raised in a subsequent appeal (T 636/97).