Any person claiming any estate or interest in such lands adverse to the terms of the decree, who has not been personally served with notice, as is provided in section 527.200, or who has not entered his appearance in the cause and answered the petition, as provided in section 527.210, may enter his appearance in the cause at any time within two years after the entry of the decree, and, on his motion, after giving twenty days’ notice to the petitioner or petitioners, or any person claiming by, through or under him, her or them, such proceedings shall be opened for the purpose of hearing, upon proof duly taken, any claim of title or interest to or in the lands which may be produced by the person making such motion; and on hearing such motion, and evidence and proof thereupon submitted, the court shall adjudge the ownership and title of the lands according to the evidence adduced, modifying its former decree as the evidence and nature of the case shall in justice and equity require; and if no motion to open such proceedings shall be made within two years from the entering of such decree, the same shall be conclusive against all persons claiming an estate or interest in the lands adverse to the rights of its petitioner, as defined in the decree, except infants and mentally incapacitated persons, who shall be allowed respectively two years after their disability is removed to appear and enter their motion for opening of their proceedings, and make answer to such petition or petitions.