16. a. (1) Child support orders may be modified upon a material change in circumstances.

(2) Modification of the Child Support Guideline Schedule shall not alone be a material change in circumstances for child support orders in existence on November 1, 1999.

(3) Providing support for children born to or adopted by either parent after the entry of a child support order shall not alone be considered a material change in circumstances.

(4) An order of modification shall be effective upon the date the motion to modify was filed, unless the parties agree to the contrary or the court makes a specific finding of fact that the material change of circumstance did not occur until a later date.

b. (1) A child support order shall not be modified retroactively regardless of whether support was ordered in a temporary order, a decree of divorce, an order establishing paternity, modification of an order of support, or other action to establish or to enforce support.

(2) All final orders shall state whether past due support and interest has accrued pursuant to any temporary order and the amount due, if any; however, failure to state a past due amount shall not bar collection of that amount after entry of the final support order.

For a current copy of 43 O.S. 118(e)(16) click on the arrow.