diff --git a/src/opnsense/mvc/app/library/OPNsense/Core/Config.php b/src/opnsense/mvc/app/library/OPNsense/Core/Config.php
index 694cb855c..8aa9b1654 100644
--- a/src/opnsense/mvc/app/library/OPNsense/Core/Config.php
+++ b/src/opnsense/mvc/app/library/OPNsense/Core/Config.php
@@ -69,6 +69,10 @@ class Config extends Singleton
      */
     private $statusIsValid = false;
 
+    /**
+     * @var float current modification time of our known config
+     */
+    private $mtime = 0;
 
     /**
      * return last known status of this configuration (valid or not)
@@ -430,6 +434,7 @@ class Config extends Singleton
         }
 
         $this->simplexml = $this->loadFromStream($this->config_file_handle);
+        $this->mtime = fstat($this->config_file_handle)['mtime'];
         $this->statusIsValid = true;
     }
 
@@ -659,6 +664,14 @@ class Config extends Singleton
         }
     }
 
+    /**
+     * @return bool when config file underneath has changed without our instance being aware of it
+     */
+    public function hasChanged()
+    {
+        return $this->mtime != fstat($this->config_file_handle)['mtime'];
+    }
+
     /**
      * return backup file path if revision exists
      * @param $revision revision timestamp (e.g. 1583766095.9337)
@@ -728,6 +741,7 @@ class Config extends Singleton
                     $logger->info("config-event: new_config " . $backup_filename);
                 }
                 flock($this->config_file_handle, LOCK_UN);
+                $this->mtime = fstat($this->config_file_handle)['mtime'];
             } else {
                 throw new ConfigException("Unable to lock config");
             }