diff --git a/tox.ini b/tox.ini
index 54df28aa..ebe29401 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,9 @@ minversion = 2.3
 skipsdist = True
 
 [testenv]
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/upper-constraints.txt} {opts} {packages}
+install_command = pip install \
+    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/stable/stein/upper-constraints.txt} \
+    {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          OS_STDOUT_CAPTURE=1
          OS_STDERR_CAPTURE=1