A lawyer representing the estate of late To Kill A Mockingbird author Harper Lee has filed suit against the producers of Aaron Sorkin’s upcoming Broadway production based on the iconic novel. The New York Times, which first reported on the lawsuit filed this week in Alabama, asserts that Sorkin’s version in not faithful enough to the original book, which was published in 1960 and won the Pulitzer Prize.

The lawsuit, according to the NYT, came after Lee estate lawyer Tonja B. Carter saw a draft of the script, which seemingly portrays protagonist Atticus Finch as an apologist for the racial status quo rather than the ever-wise, benevolent lawyer depicted in the book. The suit says the agreement signed by Lee in 2015 — eight months before her death at age 89 — called for the adaptation to “remain faithful to the spirit of the book,” according to the NYT.

Producer Scott Rudin said in a statement the production was within the parameters of his deal with Lee, and that “the suit will be vigorously defended.​” According to the lawsuit, Carter and Rudin met in February to discuss “serious concerns about the script,” with no resolution.

“This adaptation by Aaron Sorkin of To Kill a Mockingbird is a faithful adaptation of Harper Lee’s novel, which has been crafted within the constraints of the agreement executed by both Harper Lee and the play’s producers before Ms. Lee’s death,” Rudin said. “This action undertaken by the estate of Harper Lee is an unfortunate step in a situation where there is simply artistic disagreement over the creation of a play that Ms. Lee herself wanted to see produced, and is the kind of disagreement which one expects would be worked out easily between two parties who have a mutual interest in seeing a work produced.”

He added: “The estate has an unfortunate history of litigious behavior and of both filing and being the recipient of numerous lawsuits, and has been the subject of considerable controversy surrounding its handling of the work of Harper Lee both during her illness and after her death. This is, unfortunately, simply another such lawsuit, the latest of many, and we believe that it is without merit. While we hope this gets resolved, if it does not, the suit will be vigorously defended.”

Billed on the poster as a “new play by Aaron Sorkin, To Kill a Mockingbird is set to begin previews November 1 and open December 13, with Jeff Daniels starring as Finch along with Celia Keenan-Bolger, Will Pullen and Gbenga Akinnagbe. Rudin is producing with the Lincoln Center Theater, and Bartlett Sher (The King and I) is directing.

In February 2016, Rudin announced his plan to bring Mockingbird to Broadway with Sorkin aboard to adapt the book. It has had previous stage incarnations, though none at this level — there is also a perennial amateur production in Lee’s hometown of Monroeville, AL. Rights to a first-class Broadway production were retained by Lee until Rudin began pursuing them.

The Finch described in the lawsuit might more closely resemble the devolved, racist version in Lee’s sequel Go Set A Watchman, set 20 years after Mockingbird‘s events, which came out in 2015.