diff --git a/tox.ini b/tox.ini
index 415bf26..3ef399c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,14 +6,14 @@ ignore_basepython_conflict = true
 [testenv]
 basepython = python3
 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
   -r{toxinidir}/requirements.txt
 commands = stestr run {posargs}
 
 [testenv:venv]
 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
   -r{toxinidir}/doc/requirements.txt
   -r{toxinidir}/requirements.txt
@@ -33,7 +33,7 @@ exclude=.venv,.git,.tox,dist,*lib/python*,*egg,build
 
 [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
 commands = sphinx-build -a -E -W doc/source doc/build/html