diff --git a/releasenotes/notes/deprecate-NeutronExternalNetworkBridge-7d42f1a0718da327.yaml b/releasenotes/notes/deprecate-NeutronExternalNetworkBridge-7d42f1a0718da327.yaml
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+++ b/releasenotes/notes/deprecate-NeutronExternalNetworkBridge-7d42f1a0718da327.yaml
@@ -0,0 +1,10 @@
+---
+upgrade:
+  - The ``NeutronExternalNetworkBridge`` parameter changed its default value
+    from ``br-ex`` to an empty string value. It means that by default Neutron
+    L3 agent will be able to serve multiple external networks. (It was always
+    the case for those who were using templates with the value of the parameter
+    overridden by an empty string value.)
+deprecations:
+  - The ``NeutronExternalNetworkBridge`` parameter is deprecated and will be
+    removed in a next release.