clarify that \[uXXXX] wants uppercase hex digits

1 files changed, 6 insertions, 1 deletions

diff --git a/mandoc_char.7 b/mandoc_char.7
index 230e5a6e..bd37295c 100644
--- a/mandoc_char.7
+++ b/mandoc_char.7
@@ -661,7 +661,12 @@ The escape sequence
 .Pp
 is interpreted as a Unicode codepoint.
 The codepoint must be in the range above U+0080 and less than U+10FFFF.
-For compatibility, points must be zero-padded to four characters; if
+For compatibility, the hexadecimal digits 
+.Sq A
+to
+.Sq F
+must be given as uppercase characters,
+and points must be zero-padded to four characters; if
 greater than four characters, no zero padding is allowed.
 Unicode surrogates are not allowed.
 .\" .Pp