diff --git a/appendices/configure/php.xml b/appendices/configure/php.xml
index 86d029337d..ae9ef61ac8 100644
--- a/appendices/configure/php.xml
+++ b/appendices/configure/php.xml
@@ -32,6 +32,9 @@
      <para>
       Enable safe mode by default.
      </para>
+     <para>
+      As of PHP 5.4.0 this argument no longer exists.
+     </para>
     </listitem>
    </varlistentry>
    <varlistentry xml:id="configure.with-exec-dir">
@@ -42,6 +45,9 @@
      <para>
       Only allow executables in DIR when in safe mode defaults to <literal>/usr/local/php/bin</literal>.
      </para>
+     <para>
+      As of PHP 5.4.0 this argument no longer exists.
+     </para>
     </listitem>
    </varlistentry>
    <varlistentry xml:id="configure.enable-magic-quotes">