diff --git a/reference/yar/setup.xml b/reference/yar/setup.xml
index 0f4e8e5a18..a1f9e913a2 100644
--- a/reference/yar/setup.xml
+++ b/reference/yar/setup.xml
@@ -7,7 +7,8 @@
  <section xml:id="yar.requirements">
   &reftitle.required;
   <para>
-
+   if you want to use msgpack as packager, you need compile Yar by your self
+   with ./configure --enable-msgpack
   </para>
  </section>