diff --git a/include/class.thread.php b/include/class.thread.php
index 29b7a5bdf9ffcfdeb812126c2b065d9c905a3a2a..b4c10305d09372d91c28ed74094840aa1b0eee14 100644
--- a/include/class.thread.php
+++ b/include/class.thread.php
@@ -917,7 +917,7 @@ Class ThreadEntry {
         if (!$thread)
             return false;
 
-        if (0 === strcasecmp($thread->asMessageId($from, $vers), $mid))
+        if (0 === strcasecmp($thread->asMessageId($from, $ver), $mid))
             return $thread;
     }