Mich. Comp. Laws § 418.891

Sec. 891. (1) To the extent that they are reenacted herein, all the provisions of former 1965 PA 44 apply only to personal injuries occurring on or after September 1, 1965, except as otherwise provided in that act and except for the amendment to part 2, section 4 of that act, concerning selection of physicians as provided in that act. (2) In all cases where the date of injury is on or after September 1, 1965, and the employee or his dependents would be entitled to the new maximum weekly benefit rates, the employee or his dependents shall receive, without application to the workers' compensation agency, an adjustment to the increased maximum rate as it becomes effective September 1, 1966, or September 1, 1967, for any compensable weeks subsequent to the above dates. (3) This act does not affect or impair any right accruing, accrued or acquired or any liability developing or imposed prior to the time this act takes effect, and all such rights and liabilities shall be governed by the provisions of former 1912 (1st Ex Sess) PA 10. The first adjustment to the maximum rates of weekly compensation provided previously in section 9(f) of part 2 of former 1912 (1st Ex Sess) PA 10, shall remain in effect to the extent provided in such section and the amount of change in the average weekly wage not incorporated in the first adjustment made January 1, 1969 shall be carried forward as provided in such section. (4) Notwithstanding sections 301(14) and 401(10), the amendments to this act made by 2011 PA 266 apply to personal injuries and work-related diseases incurred on or after December 19, 2011.