diff --git a/pyproject.toml b/pyproject.toml
index 295491a..03e16bc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,7 +50,7 @@ nbtest = [
     "nbmake>=1.5.0",
 ]
 style = [
-    "ruff==0.8.4",
+    "ruff==0.9.4",
     "nbqa>=1.8.5",
 ]
 lint = [
diff --git a/qiskit_addon_sqd/qubit.py b/qiskit_addon_sqd/qubit.py
index 54ad6e9..f343527 100644
--- a/qiskit_addon_sqd/qubit.py
+++ b/qiskit_addon_sqd/qubit.py
@@ -128,7 +128,7 @@ def project_operator_to_subspace(
         if verbose:  # pragma: no cover
             (
                 print(
-                    f"Projecting term {i+1} out of {hamiltonian.size}: {coefficient} * "
+                    f"Projecting term {i + 1} out of {hamiltonian.size}: {coefficient} * "
                     + "".join(pauli.to_label())
                     + " ..."
                 )