diff --git a/dev-requirements.txt b/dev-requirements.txt
index 26a6934..1f63e53 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,6 +1,6 @@
 PyYAML<=3.13
 coverage==4.5.3
-mock==3.0.5
+mock<=2.0.0
 nose==1.3.7
 nose-capturestderr==1.2
 nose-exclude==0.5.0