diff --git a/flow-to-rtdb.js b/flow-to-rtdb.js
index cbe3158..f661549 100644
--- a/flow-to-rtdb.js
+++ b/flow-to-rtdb.js
@@ -19,6 +19,7 @@ module.exports = function(RED) {
         console.log('flow-to-rtdb path='+this.path+', flowId='+this.flowId)
 
         runtime.flows.getFlow({id: this.flowId}).then((flow)=>{
+          flow.updated_at = Date.now()
           this.admin.database().ref(this.path).set(flow).then((res)=>{
             console.log('firebase set result '+res)
             console.dir(res)
diff --git a/package.json b/package.json
index cc58054..eaa3692 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "node-red-contrib-firebase-admin",
-  "version": "1.0.4",
+  "version": "1.0.5",
   "description": "A node-red module that wraps the server-side  admin SDK of firebase, firestore, et.c.",
   "main": "index.js",
   "scripts": {
diff --git a/rtdb-to-flow.html b/rtdb-to-flow.html
index cb00f88..785d74d 100644
--- a/rtdb-to-flow.html
+++ b/rtdb-to-flow.html
@@ -7,6 +7,7 @@
       name: {value:""},
       flowId: {value:""},
       path: {value:""},
+      env_var: {value:""},
       cred: {value: "", type: 'firebase-config'}
     },
     inputs:1,
@@ -45,6 +46,11 @@
         <input type="text" id="node-input-path" placeholder="Path">
     </div>
 
+    <div class="form-row">
+        <label for="node-input-env_var"><i class="icon-tag"></i> Environment variable to allow update</label>
+        <input type="text" id="node-input-env_var" placeholder="Env var">
+    </div>
+
     <div class="form-row">
         <label for="node-input-cred"><i class="icon-tag"></i> Credentials</label>
         <input type="text" id="node-input-cred" placeholder="Credentials">
diff --git a/rtdb-to-flow.js b/rtdb-to-flow.js
index 06df387..97eba2b 100644
--- a/rtdb-to-flow.js
+++ b/rtdb-to-flow.js
@@ -10,10 +10,20 @@ module.exports = function(RED) {
     const cb = (res)=>{
       //console.log('firebase get result '+res)
       //console.dir(res)
-      let val = res.val()
-      runtime.flows.updateFlow({id: val.id, flow: val})
-      //console.log('val='+val)
-      node.send({payload:val})
+      if(config.env_var && process.env[config.env_var]){
+        let val = res.val()
+        runtime.flows.getFlow({id: val.id}).then((flow)=>{
+          console.log('rtdb-to-flow old flow updated_at = '+flow.updated_at+' new flow updated_at = '+val.updated_at)
+          if(!flow.updated_at || val.updated_at > flow.updated_at){
+            console.log('updating flow...')
+            runtime.flows.updateFlow({id: val.id, flow: val})
+          }
+          //console.log('val='+val)
+          node.send({payload:val})
+        })
+      } else {
+        console.log('skipping flow update because environment variable '+config.env_var+' was either not defined or not set to true')
+      }
     }
 
     let setUpListener = (path)=>{