diff --git a/controllerconfig/controllerconfig/upgrade-scripts/29-mgmt-network-fqdn-reconfig.py b/controllerconfig/controllerconfig/upgrade-scripts/29-mgmt-network-fqdn-reconfig.py
index 9f94d0141a..7385a5ddee 100644
--- a/controllerconfig/controllerconfig/upgrade-scripts/29-mgmt-network-fqdn-reconfig.py
+++ b/controllerconfig/controllerconfig/upgrade-scripts/29-mgmt-network-fqdn-reconfig.py
@@ -71,6 +71,10 @@ def main():
             to_release = sys.argv[arg]
         elif arg == 3:
             action = sys.argv[arg]
+        elif arg == 4:
+            # optional port parameter for USM upgrade
+            # port = sys.argv[arg]
+            pass
         else:
             LOG.error("Invalid option %s." % sys.argv[arg])
             return 1