diff --git a/tox.ini b/tox.ini
index 34ac76a0c..537c797c3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -68,14 +68,18 @@ commands = {posargs}
 
 #set PYTHONHASHSEED=0 to prevent wsmeext.sphinxext from randomly failing.
 [testenv:docs]
-deps = -r{toxinidir}/doc/requirements.txt
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/doc/requirements.txt
 setenv = PYTHONHASHSEED=0
 commands =
   rm -rf doc/build
   sphinx-build -E -W --keep-going -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-deps = -r{toxinidir}/doc/requirements.txt
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/doc/requirements.txt
 whitelist_externals =
   make
 commands =