(1) Acknowledgement, approval and revocation are ineffective only if they do not satisfy the requirements pursuant to section 1594 subsections (2) to (4) and sections 1595 to 1597. Acknowledgment and approval are ineffective also in the case governed by section 1597a (3) and in the case governed by section 1597a (4) in conjunction with subsection (3).
(2) Where five years have passed since the entry in a German register of civil status, the acknowledgement is effective, even if it does not satisfy the requirements of the above provisions.