California Revenue & Taxation Code
Cal. Rev. & Tax. Code § 18415
Unless otherwise specifically provided therein, the provisions of any act:
# (a)
That affect the imposition or computation of taxes, additions to tax other than Sections 19136 or 19142, penalties, or the allowance of credits against the tax, shall be applied to taxable years beginning on or after January 1 of the year in which the act takes effect.
# (b)
That change the provisions of Sections 19023 to 19027, inclusive, (relating to payment of estimated tax) or Section 19136 or Sections 19142 to 19151, inclusive, (relating to underpayment of estimated tax) shall be applied to taxable years beginning on or after January 1 of the year immediately after the year in which the act takes effect.
# (c)
That otherwise affect the provisions of this part shall be applied on and after the date the act takes effect.
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