diff --git a/reference/filesystem/functions/realpath.xml b/reference/filesystem/functions/realpath.xml
index b4014cf395..9ad83b0f2e 100644
--- a/reference/filesystem/functions/realpath.xml
+++ b/reference/filesystem/functions/realpath.xml
@@ -82,6 +82,13 @@
         *BSD systems. <function>realpath</function> now fails in this case.
        </entry>
       </row>
+      <row>
+       <entry>5.2.1</entry>
+       <entry>
+        Prior to this version, <function>realpath</function> returned &false;
+        if <parameter>path</parameter> is an empty string or &null;.
+       </entry>
+      </row>
      </tbody>
     </tgroup>
    </informaltable>