Within thirty days after issuance of a modified child support order, the party obtaining the modification shall file a certified copy of the order with the issuing tribunal which had continuing, exclusive jurisdiction over the earlier order and in those tribunals in which that party knows the earlier order has been registered. Failure of the party obtaining the order to file a certified copy as required subjects that party to appropriate sanctions by a tribunal in which the issue of failure to file arises; however, that failure has no effect on the validity or enforceability of the modified order of the new tribunal of continuing, exclusive jurisdiction.

Full faith and credit "last-in-time" rule as applicable to sister state's divorce or custody judgment which is inconsistent with forum state's earlier judgment. 36 ALR5th 527.