; and (B) in paragraph (4)— (i) by striking elementary or secondary school each place it appears and inserting educational institution ; (ii) by striking nineteen and inserting 23 ; and (iii) by striking a diploma or equivalent certificate from a secondary school (as defined in section 202(d)(7)(c)(i) of the Social Security Act) and inserting a diploma, degree, or equivalent certificate from an institution described in section 202(d)(7)(C)(ii) of the Social Security Act . (2) Conforming amendment Section 5(c)(7) of the Railroad Retirement Act of 1974 ( 45 U.S.C. 235(c)(7) ) is amended— (A) by striking elementary or secondary school and inserting educational institution ; and (B) by striking 19 and inserting 23 . (c) Effective date The amendments made by this section shall apply to child's insurance benefits that are payable for months beginning after December 31, 2017. 6. Increase in minimum benefit for lifetime low earners based on years in the workforce (a) In general Section 215(a)(1) of the Social Security Act ( 42 U.S.C. 415(a)(1) ) is amended— (1) by redesignating subparagraph (D) as subparagraph (E); and (2) by inserting after subparagraph (C) the following new subparagraph: (D) (i) Effective with respect to the benefits of individuals who become eligible for old-age insurance benefits or disability insurance benefits (or die before becoming so eligible) after 2017, no primary insurance amount computed under subparagraph (A) may be less than the greater of— (I) the minimum monthly amount computed under subparagraph (C)