diff --git a/f5_openstack_agent/lbaasv2/drivers/bigip/irule.py b/f5_openstack_agent/lbaasv2/drivers/bigip/irule.py
index 00b1364df..7f3566688 100644
--- a/f5_openstack_agent/lbaasv2/drivers/bigip/irule.py
+++ b/f5_openstack_agent/lbaasv2/drivers/bigip/irule.py
@@ -114,7 +114,7 @@ def get_irule_full_path(self, service, vip, prefix):
         return irule_fullPath
 
     def create_specific_irule(self, service, vip, bigip, prefix=None,
-                              apiAnonymous=None):
+                              apiAnonymous=None, delete=False):
         irule_partition = vip['partition']
         irule_name = self.get_irule_name(service, prefix)
         irule_fullPath = "/" + irule_partition + "/" + irule_name
@@ -125,6 +125,15 @@ def create_specific_irule(self, service, vip, bigip, prefix=None,
             partition=irule_partition
         )
 
+        # NOTE(xxx) the 'delete' arguement and this odd snippet for
+        # leftover TOA irule campatibility. it will update leftover TOA irule
+        # to new form. Maybe delete this snippet in futrue.
+        if delete and irule_exists:
+            self.irule_helper.delete(
+                partition=irule_partition,
+                name=irule_name
+            )
+
         if not irule_exists:
             payload = dict(
                 name=irule_name,
@@ -160,7 +169,7 @@ def create_iRule(self, service, vip, bigip, **kwargs):
 
         irule_fullPath = self.create_specific_irule(
             service, vip, bigip, prefix="TOA",
-            apiAnonymous=irule_apiAnonymous)
+            apiAnonymous=irule_apiAnonymous, delete=True)
         if vip['rules']:
             if irule_fullPath not in vip['rules']:
                 vip['rules'].append(irule_fullPath)