diff --git a/tox.ini b/tox.ini
index ad96da82..efde89bd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -34,7 +34,7 @@ setenv =
 basepython = python3
 deps =
     -r{toxinidir}/doc/requirements.txt
-    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.2}
 commands =
     bash -c "rm -rf doc/build"
     sphinx-build -W --keep-going -b html doc/source doc/build/html
@@ -55,7 +55,7 @@ extensions = .rst
 basepython = python3
 deps =
     -r{toxinidir}/doc/requirements.txt
-    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.2}
 commands =
     sphinx-build -a -E -W -d releasenotes/build/doctrees --keep-going -b html releasenotes/source releasenotes/build/html