diff --git a/requirements-dev.txt b/requirements-dev.txt
index d2fba17d..4eb92ad2 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -110,7 +110,7 @@ tomlkit==0.13.3 ; python_version >= '3.7'
 
 trio==0.31.0
 
-types-python-dateutil==2.9.0.20250822
+types-python-dateutil==2.9.0.20260518
 
 types-requests==2.32.4.20250809; python_version >= '3.7'
 urllib3==2.7.0 ; python_version >= '3.7'