diff --git a/tox.ini b/tox.ini
index d377fde..fa079e4 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,7 +10,7 @@ basepython = python3
 setenv =
   SETUPTOOLS_USE_DISTUTILS=stdlib
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/zed}
   -r{toxinidir}/test-requirements.txt
 commands = stestr run --slowest {posargs}
 
@@ -34,7 +34,7 @@ commands = {posargs}
 
 [testenv:docs]
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/zed}
   -r{toxinidir}/doc/requirements.txt
 whitelist_externals = rm
 commands =