Section 15A. (a) Whoever commits assault and battery upon a person sixty years or older by means of a dangerous weapon shall be punished by imprisonment in the state prison for not more than ten years or by a fine of not more than one thousand dollars or imprisonment in jail for not more than two and one-half years.
Whoever, after having been convicted of the crime of assault and battery upon a person sixty years or older, by means of a dangerous weapon, commits a second or subsequent such crime, shall be punished by imprisonment for not less than two years. Said sentence shall not be reduced until two years of said sentence have been served nor shall the person convicted be eligible for probation, parole, furlough, work release or receive any deduction from his sentence for good conduct until he shall have served two years of such sentence; provided, however, that the commissioner of correction may, on the recommendation of the warden, superintendent, or other person in charge of a correctional institution, or the administrator of a county correctional institution, grant to said offender a temporary release in the custody of an officer of such institution for the following purposes only: to attend the funeral of next of kin or spouse; to visit a critically ill close relative or spouse; or to obtain emergency medical services unavailable at said institution. The provisions of section eighty-seven of chapter two hundred and seventy-six relating to the power of the court to place certain offenders on probation shall not apply to any person 18 years of age or over charged with a violation of this subsection.
(b) Whoever commits an assault and battery upon another by means of a dangerous weapon shall be punished by imprisonment in the state prison for not more than 10 years or in the house of correction for not more than 21/2 years, or by a fine of not more than $5,000, or by both such fine and imprisonment.
(c) Whoever:
(i) by means of a dangerous weapon, commits an assault and battery upon another and by such assault and battery causes serious bodily injury;
(ii) by means of a dangerous weapon, commits an assault and battery upon another who is pregnant at the time of such assault and battery, knowing or having reason to know that the person is pregnant;
(iii) by means of a dangerous weapon, commits an assault and battery upon another who he knows has an outstanding temporary or permanent vacate, restraining or no contact order or judgment issued pursuant to section 18, section 34B or section 34C of chapter 208, section 32 of chapter 209, section 3, 4 or 5 of chapter 209A, or section 15 or 20 of chapter 209C, in effect against him at the time of such assault and battery; or
(iv) is 18 years of age or older and, by means of a dangerous weapon, commits an assault and battery upon a child under the age of 14;
shall be punished by imprisonment in the state prison for not more than 15 years or in the house of correction for not more than 21/2 years, or by a fine of not more than $10,000, or by both such fine and imprisonment.
(d) For the purposes of this section, ''serious bodily injury'' shall mean bodily injury which results in a permanent disfigurement, loss or impairment of a bodily function, limb or organ, or a substantial risk of death.