diff --git a/pyproject.toml b/pyproject.toml
index 4e83719..cfd93c9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,7 +53,7 @@ dev-flake8 = [
   "pydoclint == 0.7.6",
   "pydocstyle == 6.3.0",
 ]
-dev-formatting = ["black == 25.11.0", "isort == 8.0.1"]
+dev-formatting = ["black == 26.3.1", "isort == 8.0.1"]
 dev-mkdocs = [
   "Markdown == 3.10.2",
   "mike == 2.1.3",
diff --git a/tests/test_flake8_numbers.py b/tests/test_flake8_numbers.py
index 0656776..35a2438 100644
--- a/tests/test_flake8_numbers.py
+++ b/tests/test_flake8_numbers.py
@@ -2,6 +2,7 @@
 # Copyright © 2023 Frequenz Energy-as-a-Service GmbH
 
 """Tests for the flake8_numbers package."""
+
 import ast
 import tempfile