diff --git a/requirements.txt b/requirements.txt
index 99f48af..1042c2f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,12 +2,12 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-pbr>=2.0 # Apache-2.0
+pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
 # xml parsing
-lxml!=3.7.0,>=2.3 # BSD
-tempest>=12.1.0 # Apache-2.0
-oslo.config>=3.22.0 # Apache-2.0
-testtools>=1.4.0  # MIT
-six>=1.9.0
+lxml!=3.7.0,>=3.4.1 # BSD
+tempest>=17.1.0 # Apache-2.0
+oslo.config>=5.1.0 # Apache-2.0
+testtools>=2.2.0 # MIT
+six>=1.10.0 # MIT
 requests>=2.14.2 # Apache-2.0