diff --git a/reference/filesystem/functions/parse-ini-string.xml b/reference/filesystem/functions/parse-ini-string.xml
index a39122742a..d85a90a55c 100644
--- a/reference/filesystem/functions/parse-ini-string.xml
+++ b/reference/filesystem/functions/parse-ini-string.xml
@@ -75,7 +75,7 @@
     There are reserved words which must not be used as keys for
     ini files.  These include: null, yes, no, true, false, on, off, none.
     Values null, no and false results in "", yes and true results in "1".
-    Characters <literal>{}|&amp;~![()^"</literal> must not be used anywhere in
+    Characters <literal>?{}|&amp;~![()^"</literal> must not be used anywhere in
     the key and have a special meaning in the value.
    </simpara>
   </note>