diff --git a/man3/toupper.3 b/man3/toupper.3
index 320931bd4..f535218eb 100644
--- a/man3/toupper.3
+++ b/man3/toupper.3
@@ -140,8 +140,11 @@ For example, the default
 locale does not know about umlauts, so no conversion is done for them.
 .PP
 In some non-English locales, there are lowercase letters with no
-corresponding uppercase equivalent; the German sharp s is one
-example.
+corresponding uppercase equivalent;
+.\" FIXME: One day the statement about "sharp s" needs to be reworked,
+.\" since there is nowadays a capital "sharp s" that has a codepoint
+.\" in Unicode 5.0; see https://en.wikipedia.org/wiki/Capital_%E1%BA%9E
+the German sharp s is one example.
 .SH SEE ALSO
 .BR isalpha (3),
 .BR newlocale (3),