diff --git a/pyproject.toml b/pyproject.toml
index c8c047b..900bf3c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,10 +53,10 @@ dev-flake8 = [
   "pydoclint == 0.8.3",
   "pydocstyle == 6.3.0",
 ]
-dev-formatting = ["black == 25.9.0", "isort == 8.0.1"]
+dev-formatting = ["black == 26.3.1", "isort == 8.0.1"]
 dev-mkdocs = [
   "Markdown == 3.10.2",
-  "black == 25.9.0",
+  "black == 26.3.1",
   "mike == 2.1.4",
   "mkdocs-gen-files == 0.6.1",
   "mkdocs-literate-nav == 0.6.3",
diff --git a/src/frequenz/core/id.py b/src/frequenz/core/id.py
index 1b4787c..1abb1b7 100644
--- a/src/frequenz/core/id.py
+++ b/src/frequenz/core/id.py
@@ -61,7 +61,6 @@ class CustomNameForId(BaseId, str_prefix="CST", allow_custom_name=True):
     ```
 '''
 
-
 import logging
 from typing import Any, ClassVar, Self, cast
 
diff --git a/tests/math/test_interval.py b/tests/math/test_interval.py
index 7cc2097..97af018 100644
--- a/tests/math/test_interval.py
+++ b/tests/math/test_interval.py
@@ -3,7 +3,6 @@
 
 """Tests for the collections module."""
 
-
 from typing import Self
 
 import pytest
diff --git a/tests/test_module.py b/tests/test_module.py
index 3c27422..0d9f6ab 100644
--- a/tests/test_module.py
+++ b/tests/test_module.py
@@ -3,7 +3,6 @@
 
 """Tests for the log module."""
 
-
 import pytest
 
 from frequenz.core.module import get_public_module_name