Kan. Stat. Ann. § 84-2a-202
Terms with respect to which the confirmatory memoranda of the parties agree or which are otherwise set forth in a writing intended by the parties as a final expression of their agreement with respect to such terms as are included therein may not be contradicted by evidence of any prior agreement or of a contemporaneous oral agreement but may be explained or supplemented:
L. 1991, ch. 295, § 11; February 1, 1992.