diff --git a/requirements.txt b/requirements.txt
index 81e68b41..3b29528d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,6 @@
-d2to1
-flake8
-pbr
+d2to1>=0.2.10,<0.3
+pbr>=0.5.10,<0.6
+
+pep8==1.4.5
+pyflakes==0.7.2
+flake8==2.0