Mo. Rev. Stat. § 1.160

1.160. Effect of repeal of penal statute. — No offense committed and no fine, penalty or forfeiture incurred, or prosecution commenced or pending previous to or at the time when any statutory provision is repealed or amended, shall be affected by the repeal or amendment, but the trial and punishment of all such offenses, and the recovery of the fines, penalties or forfeitures shall be had, in all respects, as if the provision had not been repealed or amended, except that all such proceedings shall be conducted according to existing procedural laws.

(RSMo 1939 § 4861, A.L. 1957 p. 587, A.L. 1993 S.B. 180, A.L. 2005 H.B. 353) Prior revisions: 1929 § 4468; 1919 § 3709; 1909 § 4920 (1972) Where defendant was convicted of possession of narcotic drug and sentenced to three years imprisonment, his appeal argued and submitted on September 27, 1971, but prior to submission on August 31, 1971, appellant filed "Alternative Motion for Reduction of Sentence" based upon an amendment, effective September 28, 1971, of statute which reduced punishment for his offense to confinement in county jail for not more than one year or fine of $1,000, or both, supreme court remanded cause for assessment of punishment and judgment under the law as amended. State v. Reiley (Mo.), 476 S.W.2d 473. (1972) Where appellant's conviction and sentence for possession of marijuana occurred at a time when the first conviction for that offense was a felony regardless of amount of marijuana involved and while appeal was pending an amendment to the law to make possession of thirty-five grams or less a misdemeanor became effective, the cause was remanded for assessment of punishment under the law as amended. State v. Hawkins (Mo.), 482 S.W.2d 477. (1974) Held that when license was reinstated prior to effective date of amendatory act providing for elimination of points on reinstatement the act could not be applied retroactively. Ritter v. Schaffner (A.), 504 S.W.2d 207. (1990) Where statute specifying punishment in effect at time of defendant's arrest was subsequently repealed and new statute, providing for lesser punishment, became effective few days prior to trial, defendant was entitled to benefit of reduced punishment. State v. Wright, 797 S.W.2d 811 (Mo. App.). (2018) For purposes of this section, a parole eligibility provision within a statute defining an offense affects the prosecution, penalty, or punishment of offense, thus amended version of involuntary manslaughter statute was not retroactively applicable to parole eligibility for prisoner. Fields v. Missouri Bd. of Probation and Parole, 559 S.W.3d 12 (W.D.Mo.).