An 11-year-old research paper describing Treefinder, a computer program used by evolutionary biologists, has been retracted after the program’s developer banned its use in European countries he deemed too friendly to refugees.

In September, German scientist Gangolf Jobb announced on his website that researchers in eight European countries, including Germany and the United Kingdom, were no longer allowed to use Treefinder, which builds phylogenetic trees from sequence data. “I am no longer willing to support with my work the political system in Europe and Germany,” Jobb wrote. “In particular, I disagree with immigration policy. Immigration to my country harms me, it harms my family, it harms my people. Whoever invites or welcomes immigrants to Europe and Germany is my enemy.”

The move sparked outrage among some scientists, and now, BMC Evolutionary Biology has pulled the 2004 paper describing the software because the license change “breaches the journal’s editorial policy on software availability.” The retraction was first reported by the website Retraction Watch yesterday.

Jobb told Retraction Watch that a scientist can still use Treefinder “as long as he or she does it in one of the allowed countries and is personally present there.” The retraction notice explains that the other authors of the article, Arndt von Haeseler and Korbinian Strimmer, “have no control over the licensing of the software and support the retraction.”