diff --git a/requirements.txt b/requirements.txt
index 10bc330..bbc8681 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ pyasn1-modules==0.0.8     # via service-identity
 pyasn1==0.1.9             # via cryptography, pyasn1-modules, service-identity
 PyCrypto==2.6.1
 PyOpenSSL==0.15.1
-python-dateutil==1.5      # via txaws
+python-dateutil==2.4.2      # via txaws
 PyTZ==2015.7
 service-identity==14.0.0  # via twisted
 six==1.10.0               # via cryptography, pyopenssl