SECTION 1.  Section 81U of chapter 41 of the General Laws, as appearing in the 2010 Official Edition, is hereby amended by adding the following paragraph:-

In any city or town which has accepted the provisions of this paragraph, in the case of approval or disapproval of a definitive subdivision plan by action of the planning board, the planning board shall send notice of such approval to all persons that they were required to give the initial notice of the public hearing and shall inform all persons of their right to appeal and the time in which such appeal must be filed. The petitioner who seeks approval by reason of failure of the planning board to act within the time prescribed shall notify the city or town clerk in writing, within 14 days from the expiration of the approval period required in Section 81U or extended time, if applicable, of such approval. That notice shall be sent by mail to all persons that were required to receive the initial notice of the public hearing and it shall specify that appeals, if any, shall be filed within 20 days after the date the city or town clerk received such written notice from the petitioner that the board failed to act within the time prescribed.