diff --git a/reference/strings/functions/hex2bin.xml b/reference/strings/functions/hex2bin.xml
index d8a62e5991..761d0e0db3 100644
--- a/reference/strings/functions/hex2bin.xml
+++ b/reference/strings/functions/hex2bin.xml
@@ -48,8 +48,8 @@
  <refsect1 role="errors">
   &reftitle.errors;
   <para>
-   If the hexadecimal input string is of odd length an <constant>E_WARNING</constant>
-   level error is thrown.
+   If the hexadecimal input string is of odd length or invalid hexadecimal string
+   an <constant>E_WARNING</constant> level error is thrown.
   </para>
  </refsect1>
 
@@ -65,6 +65,12 @@
       </row>
      </thead>
      <tbody>
+      <row>
+       <entry>5.5.1</entry>
+       <entry>
+        A warning is thrown if the input string is invalid hexadecimal string.
+       </entry>
+      </row>
       <row>
        <entry>5.4.1</entry>
        <entry>