diff --git a/releasenotes/notes/deprecate-config-forbid_global_implied_dsr-e64cfa66e6e3ded5.yaml b/releasenotes/notes/deprecate-config-forbid_global_implied_dsr-e64cfa66e6e3ded5.yaml
new file mode 100644
index 0000000..2b63402
--- /dev/null
+++ b/releasenotes/notes/deprecate-config-forbid_global_implied_dsr-e64cfa66e6e3ded5.yaml
@@ -0,0 +1,5 @@
+---
+deprecations:
+  - The config option ``forbid_global_implied_dsr`` from the ``IdentityFeature``
+    group is now deprecated. This feature flag was introduced to support
+    testing of old OpenStack versions which are not supported anymore.
diff --git a/tempest/config.py b/tempest/config.py
index 00c69b0..fe2ba54 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -223,7 +223,11 @@
     cfg.BoolOpt('forbid_global_implied_dsr',
                 default=False,
                 help='Does the environment forbid global roles implying '
-                     'domain specific ones?'),
+                     'domain specific ones?',
+                deprecated_for_removal=True,
+                deprecated_reason="This feature flag was introduced to "
+                                  "support testing of old OpenStack versions, "
+                                  "which are not supported anymore"),
     cfg.BoolOpt('security_compliance',
                 default=False,
                 help='Does the environment have the security compliance '