(a)(1) The statutes constituting the substantive law in effect at the time the crime is committed shall apply to compute the sentence term and the release dates. No subsequent change in the statute constituting substantive law shall be applied if that law adversely affects the inmate. Changes in statute constituting substantive law that benefit the inmate may be applied to compute the inmate's sentence term and the release dates, but shall not be required to be applied except in the computation of parole eligibility.

1. (2) Parole eligibility shall be computed by applying the statute in effect at the time the inmate committed the crime for which imprisoned unless subsequent changes in the statute provide an earlier parole date. If the amendment would yield an earlier parole eligibility date, that amendment shall be applied. Statutes establishing the formula for computation of parole eligibility shall be considered substantive law and not procedural law.

   1. (b) Any statute or regulation that has been repealed or revoked shall continue to apply to sentences of inmates if other statutes, regulations, or the principles of constitutional law require its terms to be applied to that inmate, or if law permits its continued application and the policy of the department of corrections is to continue its application for reasons of fairness or economy.

   2. (c) The following chart shall establish the description of categories of law systems applicable to sentences of inmates who are subject to the custody of the secretary of corrections:

      TITLE OF LAW SYSTEM	EFFECTIVE DATE OF APPLICATION	SESSION LAW OR STATUTORY REFERENCE
      (1) "Old code"	All before July 1970
      (2) "New code"	After July 1, 1980
      (3) Penal reform act of 1973	After July 1, 1974	S.B. 72, L. 1973, ch. 339
      (4) "Firearms mandatory," "mandatory firearms," "mandatory gun," "gun act," all referring to the combination of mandatory prison term and prohibition of parole before minimum is served.	After July 1, 1976	K.S.A. 21-4618 and K.S.A. 22-3717. L. 1976, ch. 168
      (5) "Parole eligibility reform law"	On and after January 1, 1979	K.S.A. 22-3717, L. 1978, ch. 120
      (6) "Aid and abet parole limitation"	After July 1, 1981	K.S.A. 22-3717, L. 1981, ch. 156
      (7) "Parole eligibility law split"	After July 1, 1981	K.S.A. 22-3717, 22-3717a, L. 1981, ch. 156
      (8) "Sentence toughening law" or "legislative good time credit law"	After July 1, 1982	H.B. 3104 and H.B. 2757, L. 1982, ch. 137 and 150
      (9) "Previous consecutive credit limitation law"	After July 1, 1983	H.B. 2212, L. 1983, ch. 111, K.S.A. 21-4608(6), (d) and (e)
      (10) "Sentencing guidelines act"	On or after July 1, 1993	S.B. 423, L. 1993, ch. 291, K.S.A. 21-4701 et seq. and K.S.A. 22-3717

   3. (d) The history of the pertinent statutes shall be reviewed to determine the form of the law applicable at the time the crime was committed, as follows:
2. (1) K.S.A. 21-4608—Prior law: K.S.A. 62-1512, G.S. 1868, ch. 82, § 250, R.S. 1923, 62-1512, L. 1963, ch. 306, § 1, June 30, 1963, Repealed L. 1969, ch. 180, July 1, 1970; K.S.A. 62-2251, L. 1957, ch. 331, § 26; July 1, 1957, Repealed L. 1969, ch. 180; July 1, 1970; L. 1969, ch. 180, § 21-4608, July 1, 1970; L. 1978, ch. 120, § 8; January 1, 1979; L. 1982, ch. 150, § 1, July 1, 1982; L. 1983, ch. 111, § 1, July 1, 1983.
3. (2) K.S.A. 22-3717, L. 1970, ch. 129, § 22-3717, July 1, 1970; [L. 1972, ch. 317, § 90, Never Effective], L. 1973, ch. 339, § 88, July 1, 1974; L. 1974, ch. 403, § 10, July 1, 1974; L. 1975, ch. 203, § 1, July 1, 1975; L. 1976, ch. 168, § 2, July 1, 1976; L. 1978, ch. 120, § 13, January 1, 1979; L. 1979, ch. 94, § 2, July 1, 1979; L. 1981, ch. 156, § 1, July 1, 1981; L. 1982, ch. 137, § 3, July 1, 1982; L. 1982, ch. 150, § 2, July 1, 1982.

4. (3) K.S.A. 22-3717a, L. 1981, ch. 156, § 2, July 1, 1981, Repealed L. 1982, ch. 137, § 4, July 1, 1982.

   1. (e) Statutes specifically relating to the granting of credit for time served shall be applied according to the terms, the court's order, and the statute, and their histories shall be described as follows:
5. (1) K.S.A. 21-4614. Prior law K.S.A. 62-1533, L. 1969, ch. 180, § 21-4614; L. 1979, ch. 124, § 13; L. 1972, ch. 317, § 101; L. 1973, ch. 339, § 72; L. 1980, ch. 104, § 2, April 24, 1980.
6. (2) K.S.A. 21-4608 [see subsection (d)].
7. (3) K.S.A. 22-3431. Prior law K.S.A. 62-1537; L. 1970, ch. 129, § 22-3431; L. 1971, ch. 114, § 8, July 1.
8. (4) K.S.A. 22-3717 [see subsection (d)].
9. (5) K.S.A. 22-3717a [see subsection (d)].
10. (6) K.S.A. 21-4614a. L. 1988, ch. 115, § 4, July 1, 1988; L. 1989, ch. 92, §5, July 1, 1989.

(Authorized by K.S.A. 75-5251, K.S.A. 75-5210; implementing K.S.A. 75-5251, K.S.A. 75-5210; effective, T-84-32, Nov. 23, 1983; effective May 1, 1984; amended Sept. 6, 2002.)