diff --git a/pyramid/pyramidsite/requirements.txt b/pyramid/pyramidsite/requirements.txt
index 262ab58..46d257d 100644
--- a/pyramid/pyramidsite/requirements.txt
+++ b/pyramid/pyramidsite/requirements.txt
@@ -13,7 +13,7 @@ pyramid-mako==1.1.0
 repoze.lru==0.7
 translationstring==1.3
 venusian==3.0.0
-waitress==1.4.4
+waitress==2.1.1
 WebOb==1.8.6
 zope.deprecation==4.4.0
 zope.interface==5.1.0