delegate) under this section or such amendments, and (ii) on or before the last day of the first plan year beginning after December 31, 2021, or such later date as the Secretary of the Treasury (or delegate) may prescribe. In the case of a governmental or collectively bargained plan to which subparagraph (B) or (C) of subsection (a)(4) applies, clause (ii) shall be applied by substituting the date which is 2 years after the date otherwise applied under such clause. (B) Conditions This subsection shall not apply to any amendment unless— (i) during the period— (I) beginning on the date the legislative or regulatory amendment described in subparagraph (A)(i) takes effect (or in the case of a plan amendment not required by such legislative or regulatory amendment, the effective date specified by the plan), and (II) ending on the date described in subparagraph (A)(ii) (or, if earlier, the date the plan amendment is adopted), the plan is operated as if such plan amendment were in effect