1. Legal acts referred to in Articles 20, 22 and 25 concerning an EU trade mark shall have effects vis-à-vis third parties in all the Member States only after entry in the Register. Nevertheless, such an act, before it is so entered, shall have effect vis-à-vis third parties who have acquired rights in the trade mark after the date of that act but who knew of the act at the date on which the rights were acquired.
2. Paragraph 1 shall not apply in the case of a person who acquires the EU trade mark or a right concerning the EU trade mark by way of transfer of the whole of the undertaking or by any other universal succession.
4. Until such time as common rules for the Member States in the field of bankruptcy enter into force, the effects vis-à-vis third parties of bankruptcy or similar proceedings shall be governed by the law of the Member State in which such proceedings are first brought within the meaning of national law or of conventions applicable in this field.