(1) Any country outside the Union may accede to this Act and thereby become party to this Convention and a member of the Union. Instruments of accession shall be deposited with the Director General.
(a) Subject to subparagraph (b), this Convention shall enter into force with respect to any country outside the Union three months after the date on which the Director General has notified the deposit of its instrument of accession, unless a subsequent date has been indicated in the instrument deposited. In the latter case, this Convention shall enter into force with respect to that country on the date thus indicated.
(b) If the entry into force according to subparagraph (a) precedes the entry into force of Articles 1 to 21 and the Appendix according to Article 28 (2) (a), the said country shall, in the meantime, be bound, instead of by Articles 1 to 21 and the Appendix, by Articles 1 to 20 of the Brussels Act of this Convention.