Jacobsen v. Katzer

Jacobsen (plaintiff), through an open-source group, created DecoderPro, free software for programming model-train decoder chips, distributed under an artistic license requiring users who modified the code to meet specified conditions (like making modifications freely available) or else negotiate separate terms with Jacobsen. Katzer (defendant), through his company, downloaded and modified DecoderPro's code for use in a competing program without meeting the license's conditions or negotiating alternate terms. Jacobsen sued for copyright infringement; Katzer argued the open-source license meant he could not be liable in copyright, only in contract. The district court agreed with Katzer, and Jacobsen appealed.