diff --git a/reference/parle/pattern.matching.xml b/reference/parle/pattern.matching.xml
index 1a5f40e262..88854b23fd 100644
--- a/reference/parle/pattern.matching.xml
+++ b/reference/parle/pattern.matching.xml
@@ -8,7 +8,7 @@
   Parle supports regex matching similar to flex. Also supported are the following POSIX character sets: <literal>[:alnum:]</literal>, <literal>[:alpha:]</literal>, <literal>[:blank:]</literal>, <literal>[:cntrl:]</literal>, <literal>[:digit:]</literal>, <literal>[:graph:]</literal>, <literal>[:lower:]</literal>, <literal>[:print:]</literal>, <literal>[:punct:]</literal>, <literal>[:space:]</literal>, <literal>[:upper:]</literal> and <literal>[:xdigit:]</literal>.
  </para>
  <para>
-	 The Unicode character classes are currently not supported. A particular encoding can be mapped with a correctly constructed regex. For example, to match the EURO symbol encoded in UTF-8, the regular expression <literal>[\xe2][\x82][\xac]</literal> can be used. The pattern for an UTF-8 encoded string could be <literal>[ -\x7f]{+}[\x80-\xbf]{+}[\xc2-\xdf]{+}[\xe0-\xef]{+}[\xf0-\xff]+</literal>.
+	 The Unicode character classes are currently not enabled by default, pass --enable-parle-utf32 to make them available. A particular encoding can be mapped with a correctly constructed regex. For example, to match the EURO symbol encoded in UTF-8, the regular expression <literal>[\xe2][\x82][\xac]</literal> can be used. The pattern for an UTF-8 encoded string could be <literal>[ -\x7f]{+}[\x80-\xbf]{+}[\xc2-\xdf]{+}[\xe0-\xef]{+}[\xf0-\xff]+</literal>.
  </para>
  <section xml:id="parle.regex.chars">
   <title>Character representations</title>