; and (B) in subparagraph (B), in the flush text following clause (viii), by striking If any person commits such a violation after a prior conviction for a felony drug offense has become final and inserting the following: If any person commits such a violation after a prior conviction for a serious drug felony or serious violent felony has become final . (b) Controlled substances Import and Export Act amendments Section 1010(b) of the Controlled Substances Import and Export Act ( 21 U.S.C. 960(b) ) is amended— (1) in paragraph (1), in the flush text following subparagraph (H), by striking If any person commits such a violation after a prior conviction for a felony drug offense has become final, such person shall be sentenced to a term of imprisonment of not less than 20 years and inserting If any person commits such a violation after a prior conviction for a serious drug felony or serious violent felony has become final, such person shall be sentenced to a term of imprisonment of not less than 15 years ; and (2) in paragraph (2), in the flush text following subparagraph (H), by striking felony drug offense and inserting serious drug felony or serious violent felony . (c) Applicability to pending and past cases (1) Pending cases This section, and the amendments made by this section, shall apply to any offense that was committed before the date of enactment of this Act, if a sentence for the offense has not been imposed as of such date of enactment. (2) Past cases (A) Sentence reduction (i) In general In the case of a defendant who, before the date of enactment of this Act, was convicted of an offense for which the penalty is amended by this section and was sentenced to a term of imprisonment for the offense, a term of imprisonment may be reduced only if— (I) the defendant has not been convicted of any serious violent felony