diff --git a/tox.ini b/tox.ini
index f8bb0485d..cb16b36f1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,7 +29,7 @@ commands =
   rm -f .testrepository/times.dbm
   stestr run {posargs}
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2025.2}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 allowlist_externals =
@@ -41,7 +41,7 @@ allowlist_externals =
 allowlist_externals =
   rm
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2025.2}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands =
@@ -132,7 +132,7 @@ commands=pip-missing-reqs -d --ignore-file=designate/tests/* designate
 # This environment is called from CI scripts to test and publish
 # the API Ref to docs.openstack.org.
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2025.2}
   -r{toxinidir}/doc/requirements.txt
 commands =
   rm -rf api-ref/build
@@ -140,7 +140,7 @@ commands =
 
 [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/2025.2}
   -r{toxinidir}/doc/requirements.txt
 commands =
     rm -rf releasenotes/build