"This revenue procedure modifies the interim amendment deadline set forth in section 15.04(1) of Rev. Proc. 2016-37 ... as modified by Rev. Proc. 2017-41 ... and Rev. Proc. 2020-40 ... to provide that an interim amendment made to a pre-approved plan qualified under Section 401(a) of the Internal Revenue Code is adopted timely if the amendment is adopted by the end of the second calendar year after the calendar year in which the change in qualification requirements is effective with respect to the plan. Under this modification, the interim amendment deadline is no longer determined with reference to Section 401(b), and, accordingly, an employer's tax-filing deadline is no longer relevant in determining the date by which an interim amendment must be adopted. As a result of this modification, the interim amendment deadline set forth in section 15.06(1)(a) of Rev. Proc. 2016-37, which is applicable to a governmental plan within the meaning of Section 414(d), and which is determined by reference to the interim amendment deadline for a plan that is not a governmental plan, is modified. Also, consistent with this modification, section 15.06(2) of Rev. Proc. 2016-37, which provides a special rule for determining the tax-filing deadline applicable to a tax-exempt employer that is no longer relevant in light of the modified interim amendment deadline, is deleted."