diff --git a/requirements.txt b/requirements.txt
index fe5ab09..94eefd3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-pbr>=0.6,!=0.7,<1.0
-Babel>=1.3
-retrying>=1.2.3
-six>=1.9.0
+pbr>=1.6  # Apache-2.0
+Babel>=2.3.4  # BSD
+retrying>=1.2.3,!=1.3.0 # Apache-2.0
+six>=1.9.0  # MIT