diff --git a/pyproject.toml b/pyproject.toml
index 3970e6d..3641c9e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ authors = [
 ]
 description = "The pyhoff package allows easy accessing of Beckhoff and Wago terminals with python over ModBus TCP"
 readme = "README.md"
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 classifiers = [
     "Programming Language :: Python :: 3",
     "License :: OSI Approved :: MIT License",
@@ -24,6 +24,20 @@ build-backend = "setuptools.build_meta"
 [tool.setuptools.packages.find]
 where = ["src"]
 
+[project.optional-dependencies]
+dev = [
+    "pytest", "flake8", "mypy"
+]
+
+[tool.mypy]
+files = ["src"]
+strict = true
+warn_return_any = true
+warn_unused_configs = true
+check_untyped_defs = true
+no_implicit_optional = true
+show_error_codes = true
+
 [tool.pytest.ini_options]
 minversion = "6.0"
 addopts = "-ra -q"