Artikel 23

If a Contracting State has more than one legal system in matters of divorce or legal separation, it may, at the time of signature, ratification or accession, declare that this Convention shall extend to all its legal systems or only to one or more of them, and may modify its declaration by submitting another declaration at any time thereafter.
These declarations shall be notified to the Ministry of Foreign Affairs of the Netherlands, and shall state expressly the legal systems to which the Convention applies.
Contracting States may decline to recognize a divorce or legal separation if, at the date on which recognition is sought, the Convention is not applicable to the legal system under which the divorce or legal separation was obtained.