(a) Notwithstanding paragraph (i) of subdivision (4) of section 5 of chapter 32 of the General Laws, an active or inactive member of the teachers’ retirement system or the Boston retirement system who: (i) is a teacher as defined in section 1 of said chapter 32; (ii) became eligible for membership in either the teachers’ retirement system or the Boston retirement system before July 1, 2001; (iii) began contributing to the teachers’ retirement system or the Boston retirement system before July 1, 2001; and (iv) was eligible but did not provide a written election to participate in the alternative superannuation retirement benefit program established under said subdivision (4) of said section 5 of said chapter 32 to the teachers’ retirement system or the Boston retirement system before July 1, 2001 or declined to participate in the alternative superannuation retirement benefit program before July 1, 2001, shall have a new 1-time opportunity to elect to participate in said alternative superannuation retirement benefit program pursuant to this act.

 (b) An eligible member may make the election provided under subsection (a) on or after the effective date of this act but not later than June 30, 2027.

 (c) An eligible member who elects to participate in the alternative superannuation retirement benefit program under this act shall make contributions at the rate of 11 per cent pursuant to clause (vi) of subsection (b) of section 22 of chapter 32 of the General Laws and shall provide make-up contributions equal to the difference between the (i) amount that would have been withheld as regular deductions at the rate of 11 per cent from the member’s regular compensation pursuant to said section 22 of said chapter 32, retroactive to July 1, 2001; and (ii) regular deductions actually withheld from the member’s regular compensation over such period, plus actuarial assumed interest at the rate in effect from year to year, compounded annually. The member shall make such make-up contributions in one sum, or in installments, under such terms and conditions as the relevant retirement system may require.

 (d) An election made pursuant to this act shall be irrevocable. If an eligible member does not elect to participate within the time period prescribed in subsection (b), the member shall be considered to have affirmatively elected not to participate in the alternative superannuation retirement benefit program.

 (e) An eligible member, who elects to participate in the alternative superannuation retirement benefit program pursuant to this act and pays additional retirement contributions pursuant to said program, but who does not complete the creditable service or teaching service requirements of paragraph (i) of subdivision (4) of section 5 of chapter 32 of the General Laws, shall, upon termination from membership in or retirement from the relevant retirement system, be reimbursed for any additional contributions, plus regular interest, as determined by the teachers’ retirement board or the Boston retirement board.

 (f) The teachers’ retirement system and the Boston retirement system shall notify eligible active or inactive members of the teachers’ retirement system and the Boston retirement system and school districts about the opportunity established in subsection (a).