diff --git a/pyproject.toml b/pyproject.toml
index fd2936c7..82ab7431 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -47,7 +47,7 @@ dev = [
   "pytest>=9.1,<10.0",
   "pytest-cov>=7.1,<8.0",
   "pytest-xdist~=3.8",
-  "python-dateutil~=2.9",
+  "python-dateutil>=2.9,<4.0",
   "ruff~=0.17",
   "types-python-dateutil~=2.9",
 
diff --git a/uv.lock b/uv.lock
index 23ead78d..56858892 100644
--- a/uv.lock
+++ b/uv.lock
@@ -68,7 +68,7 @@ dev = [
     { name = "pytest", specifier = ">=9.1,<10.0" },
     { name = "pytest-cov", specifier = ">=7.1,<8.0" },
     { name = "pytest-xdist", specifier = "~=3.8" },
-    { name = "python-dateutil", specifier = "~=2.9" },
+    { name = "python-dateutil", specifier = ">=2.9,<4.0" },
     { name = "python-semantic-release", specifier = ">=10.7.0,<10.8.0" },
     { name = "ruff", specifier = "~=0.17" },
     { name = "sphinx", specifier = ">=4.0,<9.0" },
@@ -1229,14 +1229,15 @@ wheels = [
 
 [[package]]
 name = "python-dateutil"
-version = "2.9.0.post0"
+version = "3.0.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "six" },
+    { name = "tzdata" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/66/c0/0c8b6ad9f17a802ee498c46e004a0eb49bc148f2fd230864601a86dcf6db/python-dateutil-2.9.0.post0.tar.gz", hash = "sha256:37dd54208da7e1cd875388217d5e00ebd4179249f90fb72437e91a35459a0ad3", size = 342432, upload-time = "2024-03-01T18:36:20.211Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/0e/df/f15f80383f152452d8985b36d95cb8751f901a3e0ff4cd27f7e118f168e2/python_dateutil-3.0.0.tar.gz", hash = "sha256:7ebcb3c29a92f3ceafe79a7a48a5c45677e9e004bbeec5742ac0bbb00560b7a2", size = 271066, upload-time = "2026-10-21T23:41:45.075Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/ec/57/56b9bcc3c9c6a792fcbaf139543cee77261f3651ca9da0c93f5c1221264b/python_dateutil-2.9.0.post0-py2.py3-none-any.whl", hash = "sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427", size = 229892, upload-time = "2024-03-01T18:36:18.57Z" },
+    { url = "https://files.pythonhosted.org/packages/5a/17/cebee01d1c0c1441174cf0456ddc91b280d79acb65340c05e41d77866ee8/python_dateutil-3.0.0-py2.py3-none-any.whl", hash = "sha256:3c79630202e4152c6add678446984236efe4f57e84d8e892aab0637bab82e9fd", size = 94659, upload-time = "2026-10-21T23:41:43.431Z" },
 ]
 
 [[package]]
@@ -1802,6 +1803,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/67/81/4add07e5172b7ac40d8ed5ff580409a7801a4fe26d529bdd915401dabfbe/typing_inspection-0.4.4-py3-none-any.whl", hash = "sha256:65b8397ba37ccbce054456aaccddfc91e6e3083c92824df348d96ca832f3f147", size = 14750, upload-time = "2026-08-12T12:37:24.648Z" },
 ]
 
+[[package]]
+name = "tzdata"
+version = "2026.5"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/d9/68/f1b440335057bfce71b6e50a9d09445aa2ecbd08359a337976627b8409e7/tzdata-2026.5.tar.gz", hash = "sha256:8cc73c0a0bfca7dbfa59235d60b2eff82231dee33f53d206db1acd9173cfc0a7", size = 200404, upload-time = "2026-10-03T09:23:14.143Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/94/21/1e5995a1c920cce14e4bffae20c665ec10e7ed03ab25e006cd741092b718/tzdata-2026.5-py2.py3-none-any.whl", hash = "sha256:b683bd1b6659ddcd810ff02ad09ba821d4bf1065072805063eb35c49617905ac", size = 347996, upload-time = "2026-10-03T09:23:12.535Z" },
+]
+
 [[package]]
 name = "urllib3"
 version = "2.7.0"