A recent ruling by the United States Court of Appeals for the Federal Circuit, Jacobsen v. Katzer, No. 08-1001 (Fed. Cir. Aug. 13, 2008), found that the terms of an open source license are “enforceable copyright conditions,” allowing a plaintiff to assert a copyright infringement claim if a user of open source software fails to comply with the terms of the license.

The Federal Circuit decision offers an important victory for proponents of open source software, supporting the continued growth in the adoption and use of open source software worldwide. For users of open source software, especially those in a commercial environment, this decision is an important reminder that although open source code may be easily obtainable online, the code is still copyrighted material and needs to be evaluated and treated within your organization as carefully as any other inbound license of third party software.

What is Open Source Software?

Open source software generally refers to software that is made publicly or freely available to users in source code and object code form. Although such software may be available free of charge, it is protected by copyright and generally governed by license terms that permit use, copying, modification, and distribution subject to certain conditions. Some of the most common open source licenses include the GNU General Public License (GPL), the MIT License, the Apache License, and the Mozilla Public License. With the rapid growth of the Internet over the past decade and the resulting technological advances making it easier to distribute and collaborate on software projects, open source software has thrived and is now accepted as part of the standard software landscape by many mainstream organizations.

Background on Jacobsen Case

Robert Jacobsen is a software developer who holds the copyright in certain code used by model railroad enthusiasts to program the chips that control model trains. Jacobsen, along with other code contributors, make this software package, known as DecoderPro, available for public use, download, and modification through an open source project hosted on SourceForge.net, a popular open source management site for developers. The DecoderPro software is licensed to users pursuant to an open source license known as the Artistic License.

Matthew Katzer is a commercial software developer, offering a competing product for model train enthusiasts known as Decoder Commander. Jacobsen sued Katzer, alleging that Katzer copied portions of the DecoderPro code and incorporated it into its competing Decoder Commander program, without complying with the Artistic License terms. In particular, Katzer did not comply with the various attribution requirements found in the Artistic License, including reference to the author’s name, the DecoderPro copyright notice, and a description of how Katzer modified the original DecoderPro source code.

Jacobsen moved for a preliminary injunction against Katzer, reasoning that Katzer’s use of the open source code in violation of the terms of the Artistic License amounted to using the copyrighted code without a valid license and thus constituted copyright infringement. Under applicable law in the 9th Circuit, irreparable harm may be presumed in a copyright infringement case showing likelihood of success on the merits. Therefore, Jacobsen argued that a preliminary injunction was warranted.

The District Court for the Northern District of California ruled against Jacobsen’s motion for preliminary injunction, finding that the plaintiff only had a cause of action for breach of the Artistic License, but not for copyright infringement. Without the infringement claim, there was no presumption of irreparable harm or entitlement to a preliminary injunction.

Circuit Court Ruling

On appeal, the Federal Circuit vacated the District Court’s ruling against a claim of copyright infringement and remanded the case for further proceedings. The Federal Circuit’s reasoning hinged on whether the requirements of the Artistic License were either (1) conditions that limit the scope of the copyright license, or (2) merely independent contractual covenants to the copyright license, which would be governed by contract law. If the requirements of the Artistic License are conditions limiting the scope of the license and the licensee acts outside this scope, the licensor can bring an action for copyright infringement.

The court explained that in general “copyright holders who engage in open source licensing have the right to control the modification and distribution of copyrighted material.” It found that the Artistic License is clear in its terms that a user is only given limited permission to modify and distribute the computer code “provided that” the user complies with the restrictive conditions of the license. Therefore, “the terms of the Artistic License are enforceable copyright conditions,” allowing the author of open source software to bring a claim for copyright infringement against a user that failed to comply with the license’s terms.


Although this case involved the Artistic License, which is not one of the more popular open source licenses, the ruling supports the enforceability of open source licenses in general. While the use of open source software has grown tremendously, some have been reluctant to adopt open source because of the perceived uncertainty surrounding the enforceability of open source licenses. Whether or not that uncertainty was ever warranted, the lack of a clear ruling in the U.S. courts focused on the issue of enforceability left some uneasy towards adopting open source. However, this ruling now supports the position that proponents of open source software and many commentators have assumed for years: use of open source software in violation of the terms of the open source license will give rise to a claim for copyright infringement.

If you are a developer that wants to release code under an open source license, this ruling should ease your apprehension as to the enforceability of the restrictions you elect to implement when you choose an open source license. If a user takes your code and violates the terms of the open source license, you may be entitled to statutory remedies under the Copyright Act, including possible preliminary injunctive relief. The Federal Circuit decision specifically discussed the role of injunctions and the restrictions found in open source licensing: “Indeed, because a calculation of damages is inherently speculative, these types of license restrictions might well be rendered meaningless absent the ability to enforce through injunctive relief.” For users of open source, this case is an important reminder that open source software needs to be evaluated and managed as carefully as any inbound commercial product being licensed by your company. When using open source software, the license terms need to be evaluated prior to use and monitored on an ongoing basis to ensure your organization’s compliance.