diff --git a/appendices/migration54.xml b/appendices/migration54.xml
index 5aed56dabf..dc9df9196a 100644
--- a/appendices/migration54.xml
+++ b/appendices/migration54.xml
@@ -112,6 +112,12 @@
      and <literal>'5 foobar'</literal> are considered non-numeric and produce a <constant>E_WARNING</constant>, but are converted
      to 12 and 5 respectively, for backward compatibility reasons.
     </simpara>
+    <simpara>
+     Note: Following code returns different result.
+    </simpara>
+    <simpara>
+     $str='abc';var_dump(isset($str['x'])); // false for PHP 5.4 or later, but true for 5.3 or less
+    </simpara>
    </listitem>
    <listitem>
     <simpara>
diff --git a/language/types/array.xml b/language/types/array.xml
index 323a2ec491..a4b5d4ef91 100644
--- a/language/types/array.xml
+++ b/language/types/array.xml
@@ -118,6 +118,61 @@ $array = [
      </listitem>
     </itemizedlist>
    </para>
+
+   <para>
+    From PHP 5.4, string offset access made consistent. As a result, some return values may be
+    different from older version. As of PHP 5.4, string offset should be integer or integer like
+    string, otherwise it will be in a warning.
+   </para>
+
+   <example>
+    <title>String offset access example</title>
+    <programlisting role="php">
+<![CDATA[
+<?php
+$str = 'abc';
+
+var_dump($str['1']);          // 5.4.0>=: "b", Older versions: "b"
+var_dump(isset($str['1']));   // 5.4.0>=: true,  Older versions: ture
+
+var_dump($str['1.0']);        // 5.4.0>=: "b" with E_WARNING, Older versions: "b"
+var_dump(isset($str['1.0'])); // 5.4.0>=: false,  Older versions: true
+
+var_dump($str['x']);          // 5.4.0>=: "a" with E_WARNING, Older versions: "a"
+var_dump(isset($str['x']));   // 5.4.0>=: false,  Older versions: true
+
+var_dump($str['1x']);         // 5.4.0>=: "b", Older versions: "b"
+var_dump(isset($str['1x']));  // 5.4.0>=: true,  Older versions: ture
+?>
+]]>
+    </programlisting>
+    &example.outputs;
+    <screen>
+<![CDATA[
+[php-5.3]$ php-5.3 test.php
+string(1) "b"
+bool(true)
+string(1) "b"
+bool(true)
+string(1) "a"
+bool(true)
+string(1) "b"
+bool(true)
+[php-5.4]$ php-5.4 test.php
+string(1) "b"
+bool(true)
+
+Warning: Illegal string offset '1.0' in /tmp/t.php on line 7
+string(1) "b"
+bool(false)
+
+Warning: Illegal string offset 'x' in /tmp/t.php on line 9
+string(1) "a"
+bool(false)
+string(1) "b"
+bool(false)
+    </screen>
+   </example>
    
    <para>
     If multiple elements in the array declaration use the same key, only the last one