diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 74a16af04ad..c071d6df366 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -3148,11 +3148,14 @@ SELECT NOT(ROW(table.*) IS NOT NULL) FROM TABLE; -- detect at least one null in
        </para>
        <para>
         Converts the first letter of each word to upper case and the
-        rest to lower case. When using the <literal>libc</literal> locale
-        provider, words are sequences of alphanumeric characters separated
-        by non-alphanumeric characters; when using the ICU locale provider,
-        words are separated according to
-        <ulink url="https://www.unicode.org/reports/tr29/#Word_Boundaries">Unicode Standard Annex #29</ulink>.
+        rest to lower case.
+       </para>
+       <para>
+        This function is primarily used for convenient
+        display, and the specific result should not be relied upon because of
+        the differences between locale providers and between different
+        ICU versions. If specific word boundary rules are desired,
+        it is recomended to write a custom function.
        </para>
        <para>
         <literal>initcap('hi THOMAS')</literal>