Making its way through Congress tomorrow, the Music Modernization Act is set to change the way artists receive royalties.

Music has come a long way since the disruptive days of Napster, but since streaming became the norm lawmakers have been slow to keep pace. When Spotify launched in 2011, there was no concrete way to identify and compensate songwriters for the millions of tracks it made available to its listeners—but the Orrin G. Hatch (the senator’s name was added to the bill late) Music Modernization Act seeks to change that. After clearing the bill on Tuesday, the Senate has ushered in new protections for how musicians make a living; including a new independent organization to administer a blanket mechanical license, and, in a first for American copyright, producers will also be inscribed into the law. One the House passes the bill, it will be up to president Donald Trump to finally make it law.

But surprisingly, despite a healthy backing from the music industry, only a handful of streaming services opposed the new legislation in its current form, backing down at the eleventh hour and allowing it to pass. On Tuesday, over 150 artists, including Kim Gordon, Stevie Nicks, and Paul McCartney, signed a letter addressed to the satellite radio company SiriusXM, accusing the company of holding up the bill when it would benefit artists. Spearheaded by songwriter Ross Golan, who has penned hits for Nicki Minaj, Selena Gomez, and Ariana Grande, the statement shows the weight of artists who are for the first update to copyright law in 20 years: “We do not want to fight and boycott your company but we will as we have other opponents. Stand with us! Be brave and take credit for being the heroes who helped the MMA become historic law!” The issue lay with music released before 1972, which SiriusXM said shouldn’t be covered by the law.

“With this bill, we are one step closer to historic reform for our badly outdated music laws,” said Hatch(R-UT), who championed the complicated bill through Congress, in a statement.