diff --git a/reference/intl/idn/idn-to-ascii.xml b/reference/intl/idn/idn-to-ascii.xml
index 00c03540af..614d3069ed 100644
--- a/reference/intl/idn/idn-to-ascii.xml
+++ b/reference/intl/idn/idn-to-ascii.xml
@@ -46,7 +46,7 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   Domain name encoded in ASCII-compatible form.
+   Domain name encoded in ASCII-compatible form. &return.falseforfailure;
   </para>
  </refsect1>
  
diff --git a/reference/intl/idn/idn-to-utf8.xml b/reference/intl/idn/idn-to-utf8.xml
index 56b635fb80..0197fe6bca 100644
--- a/reference/intl/idn/idn-to-utf8.xml
+++ b/reference/intl/idn/idn-to-utf8.xml
@@ -46,7 +46,7 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   Domain name in Unicode. In PHP5, domain name will be in UTF-8.
+   Domain name in Unicode. In PHP5, domain name will be in UTF-8. &return.falseforfailure;
   </para>
  </refsect1>