¶1This is a petition for a writ of habeas corpus brought against the superintendent of the Massachusetts Correctional Institution at Walpole for the purpose of securing a determination of the deductions from his sentence to which the petitioner was entitled under the provisions of G. L. c. 127, §§ 129, 129B and 129D. See Beaton, petitioner, 354 Mass. 670, 671 (1968). The petitioner was discharged from further imprisonment (G. L. c. 127, § 129) pending his appeal from the judgment of the Superior Court dismissing his petition. His counsel conceded at the argument that the Commissioner of Correction and the superintendent have now changed the manner in which they administer the provisions of the relevant statutes, and no sound reason has been advanced why the case has not become moot. Compare Jones v. Superintendent, Massachusetts Correctional Institution, Bridgewater, 5 Mass. App. Ct. 880 (1977). Contrast Pina v. Superintendent, Massachusetts Correctional Institution, Walpole, 376 Mass. 659, 663-664 (1978). Accordingly, we vacate the judgment appealed from with a notation that our decision is not on the merits and remand the case to the Superior Court with the direction to dismiss the petition on the ground that it is moot.
¶2So ordered.