diff --git a/tox.ini b/tox.ini
index aa65bd3..e000b43 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,7 +9,7 @@ basepython = python3
 usedevelop = True
 setenv =
    VIRTUAL_ENV={envdir}
-deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/zed}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
@@ -35,7 +35,7 @@ commands =
 
 [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}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands =
@@ -51,7 +51,7 @@ exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,.ropeproject,tools,hori
 
 [testenv:releasenotes]
 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}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html