diff --git a/pkgs/development/python-modules/niworkflows/default.nix b/pkgs/development/python-modules/niworkflows/default.nix
index d6eb920d36d4..1816cdbd20a3 100644
--- a/pkgs/development/python-modules/niworkflows/default.nix
+++ b/pkgs/development/python-modules/niworkflows/default.nix
@@ -40,16 +40,14 @@ buildPythonPackage rec {
     hash = "sha256-29ZxLuKrvgCIOMMCUpi0HHhlNlgqUrUrSCiikwecmKw=";
   };
 
-  postPatch = ''
-    substituteInPlace pyproject.toml --replace '"traits < 6.4"' '"traits"'
-  '';
+  pythonRelaxDeps = [ "traits" ];
 
-  nativeBuildInputs = [
+  build-system = [
     hatch-vcs
     hatchling
   ];
 
-  propagatedBuildInputs = [
+  dependencies = [
     attrs
     importlib-resources
     jinja2