It’s a new day for open source developers. A U.S. Federal appeals court yesterday ruled that someone releasing code under an open source license can control future use of that code using copyright law. That’s important because copyright laws carry stronger remedies—including court injunction—along with the monetary remedies available for breach of contract.

The 15-page ruling in Jacobsen v. Katzer favored Robert Jacobsen, a model train hobbyist who gave away his Java Model Railroad Interface (JMRI) software under the Artistic License for free software. “Through the collective work of many participants,” according to the ruling, “JMRI created a computer programming application called DecoderPro, which allows model railroad enthusiasts to use their computers to program the decoder chips that control model trains.”

At issue before the lower court was whether Matthew Katzer and Kamind
Associates had included algorithms from the DecoderPro project in its Decoder Commander in a manner not in compliance with the Artistic License. Decoder Commander is a commercial product that competes with DecoderPro, which is free. Compliance would have required that Kamind include the authors’ names, JMRI copyright notices and several other references, and a description of how the source code was changed from the original.

Jacobsen was initially rebuffed when seeing a preliminary injunction against Katzer by district court, which ruled:

The plaintiff claimed that by modifying the software the defendant had exceeded the scope of the license and therefore infringed the copyright. Here, however, the JMRI Project license provides that a user may copy the files verbatim or may otherwise modify the material in any way, including as part of a larger, possibly commercial software distribution. The license explicitly gives the users of the material, any member of the public, “the right to use and distribute the [material] in a more-or-less customary fashion, plus the right to make reasonable accommodations.” The scope of the nonexclusive is, therefore, intentionally broad. The condition that the user insert a prominent notice of attribution does not limit the scope of the license. Rather, Defendants’ alleged violation of the conditions of the license may have constituted a breach of the nonexclusive licenses, but does not create liability for copyright infringement where it would not otherwise exist.

The appellate court thought otherwise, and bumped it back down to the chain for further review.