Mass. Gen. Laws ch. 60 § 66
Upon the filing of such a petition the court shall forthwith cause to be made by one of its official examiners an examination of the title sufficient only to determine the persons who may be interested in the same, and shall upon the filing of the examiner's report notify all persons appearing to be interested, whether as equity owners, mortgagees, lienors, attaching creditors or otherwise, of the pendency of the petition, the notice to be sent to each by registered mail and return of receipt required, the addresses of respondents, so far as may be ascertained, being furnished by the petitioner. Such other and further notice by publication or otherwise shall be given as the court may at any time order. The notice, to be addressed "To all whom it may concern," shall contain the name of the petitioner, the names of all known respondents, a description of the land and a statement of the nature of the petition, shall fix the time within which appearance may be entered and answer filed, and shall contain a statement that unless the party notified shall appear and answer within the time fixed a default will be recorded, the petition taken as confessed, and the right of redemption forever barred.
Mass. Gen. Laws ch. 60, § 66