Jacobsen V. Katzer

Jacobsen v. Katzer was a lawsuit between Robert Jacobsen (plaintiff) and Matthew Katzer (defendant), filed March 13, 2006 in the United States District Court for the Northern District of California. The case addressed claims concerning copyright, patent invalidity, cybersquatting, and Digital Millennium Copyright Act issues relating to model train control software, developed by Jacobsen under an open source license.

The District Court first found in a summary judgement that the open source copyright did not support damages for copyright violation. This was reversed by the Circuit Court of Appeals, which held that such copyrights were enforceable. The case was settled out of court on February 16, 2010. This was a contentious case, with litigation encompassing 405 Federal District Court document filings and two appeals to the Circuit Court of Appeals.

The case is of general interest because it has clarified the enforceability of licensing for all parties (open-source software and proprietary software) under United States copyright law. It established that the conditions of the Artistic License are "enforceable copyright conditions".