diff --git a/requirements.txt b/requirements.txt
index 4e106d2..6a553d9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 graphviz==0.8
 ply==3.10
-py==1.4.34
+py==1.10.0
 -e git+git@github.com:ianno/pycolite-dev.git@e4674604fb09cf70f543f0538f405384216d7b0e#egg=pycolite
 pytest==3.1.3
 pytest-timeout==1.2.0