diff --git a/reference/outcontrol/functions/output-add-rewrite-var.xml b/reference/outcontrol/functions/output-add-rewrite-var.xml
index de8c0f9b1cda..539cee3ee1f3 100644
--- a/reference/outcontrol/functions/output-add-rewrite-var.xml
+++ b/reference/outcontrol/functions/output-add-rewrite-var.xml
@@ -45,6 +45,13 @@
     it cannot be started again.
    </simpara>
   </note>
+  <warning>
+   <simpara>
+    Prior to PHP 8.4.0, the hosts to be rewritten were set in
+    <link linkend="ini.session.trans-sid-hosts">session.trans_sid_hosts</link>
+    instead of <link linkend="ini.url-rewriter.hosts">url_rewriter.hosts</link>.
+   </simpara>
+  </warning>
  </refsect1>
 
  <refsect1 role="parameters">