Artikel 21

1. When making a notification of succession under article 17 or 18 establishing its status as a party or contracting State to a multilateral treaty, a newly independent State may, if the treaty so permits, express its consent to be bound by part of the treaty or make a choice between differing provisions under the conditions laid down in the treaty for expressing such consent or making such choice.
2. A newly independent State may also exercise, under the same conditions as the other parties or contracting States, any right provided for in the treaty to withdraw or modify any consent expressed or choice made by itself or by the predecessor State in respect of the territory to which the succession of States relates.
3. If the newly independent State does not in conformity with paragraph 1 express its consent or make a choice, or in conformity with paragraph 2 withdraw or modify the consent or choice of the predecessor State, it shall be considered as maintaining:
(a) the consent of the predecessor State, in conformity with the treaty, to be bound, in respect of the territory to which the succession of States relates, by part of that treaty; or
(b) the choice of the predecessor State, in conformity with the treaty, between differing provisions in the application of the treaty in respect of the territory to which the succession of States relates.