diff --git a/src/opnsense/mvc/app/library/OPNsense/Core/Config.php b/src/opnsense/mvc/app/library/OPNsense/Core/Config.php
index 1a8ef5a18..422a1f7ce 100644
--- a/src/opnsense/mvc/app/library/OPNsense/Core/Config.php
+++ b/src/opnsense/mvc/app/library/OPNsense/Core/Config.php
@@ -566,7 +566,7 @@ class Config extends Singleton
      */
     public function getBackupFilename($revision)
     {
-        $tmp = (float)$revision;
+        $tmp = preg_replace("/[^0-9.]/", $revision);
         $bckfilename = dirname($this->config_file) . "/backup/config-{$tmp}.xml";
         if (is_file($bckfilename)) {
             return $bckfilename;