diff --git a/language/variables.xml b/language/variables.xml
index a9b682ff2d..53482183f3 100644
--- a/language/variables.xml
+++ b/language/variables.xml
@@ -30,6 +30,9 @@
     <simpara>
      <literal>$this</literal> is a special variable that can't be
      assigned.
+     Prior to PHP 7.1.0, indirect assignment (e.g. by using
+     <link linkend="language.variables.variable">variable variables</link>)
+     was possible.
     </simpara>
    </note>