A federal judge in California has ruled that all copyright claims to the song "Happy Birthday To You" are invalid, the Los Angeles Times reports, meaning that music publisher Warner/Chappell can no longer collect licensing fees from its commercial use.

In a 43-page decision, US District Judge George King ruled that the original copyright on the song, filed by the Clayton F. Summy Co. in 1935, only covered specific piano arrangements, and not the song's lyrics. Warner/Chappell, a subsidiary of Warner Music, acquired the copyright in 1988, when it acquired a company that had obtained Summy's catalog. Warner/Chappell had reportedly earned about $2 million a year in licensing fees for the song's use in TV and movies.

"'Happy Birthday' is finally free after 80 years," Randall Newman, an attorney for the plaintiffs, told reporters following the ruling. "Finally, the charade is over. It's unbelievable."

The ruling concludes a lawsuit filed two years ago by filmmaker Jennifer Nelson, who was asked to pay $1,500 to use the tune in a documentary. Nelson and the other artists who joined her in the suit have asked Warner to return licensing fees it collected since at least 2009.

King's ruling lays out the long and complex history of "Happy Birthday," which was composed by sisters Mildred and Patty Hill in 1893, under the title "Good Morning To All." Their melody eventually evolved into the familiar birthday tune sung around the world, but King ruled that it's unclear whether the Hill sisters ever wrote the lyrics, and that there is no evidence that Summy Co. acquired its copyright. (The melody for "Happy Birthday" has long been in the public domain.)

Tuesday's decision means that anyone can use the song for commercial purposes, though Robert Brauneis, a George Washington University law professor, tells the Los Angeles Times that the ruling does not automatically place "Happy Birthday" in the public domain. Brauneis notes that the copyright may still be owned by someone else, but determining its legal owner "would be quite an interesting job."

Warner can appeal the decision with a permit from the judge, though it's not clear whether it will do so. In a statement, Warner/Chappell said it is "looking at the court's lengthy opinion and considering our options."