Mass. Gen. Laws ch. 51 § 35
Except in any city or town as to which it is otherwise provided by special law, registrars shall compare all omitted listings with the annual register of voters for the preceding year, and if it appears to their satisfaction that any of said omitted listings is that of a person entitled to vote in such preceding year they shall at any time up to and including the day of the next primary or election enter such name on the current annual register. In every case they shall require the vote by virtue of which such entry or correction is made to be attested by their clerk. Notwithstanding any inconsistent provision of this section or of any other general or special law, this section shall apply to the city of Boston and the election commissioners thereof.
Mass. Gen. Laws ch. 51, § 35