+=item * C<$num_octets = utf8::upgrade($string)>
+
+Converts in-place the internal representation of the string from an octet
+sequence in the native encoding (Latin-1 or EBCDIC) to I<UTF-X>. The
+logical character sequence itself is unchanged. If I<$string> is already
+stored as I<UTF-X>, then this is a no-op. Returns the
+number of octets necessary to represent the string as I<UTF-X>. Can be
+used to make sure that the UTF-8 flag is on, so that C<\w> or C<lc()>
+work as Unicode on strings containing characters in the range 0x80-0xFF
+(on ASCII and derivatives).
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * C<$success = utf8::downgrade($string[, $fail_ok])>
+
+Converts in-place the internal representation of the string from
+I<UTF-X> to the equivalent octet sequence in the native encoding (Latin-1
+or EBCDIC). The logical character sequence itself is unchanged. If
+I<$string> is already stored as native 8 bit, then this is a no-op. Can
+be used to
+make sure that the UTF-8 flag is off, e.g. when you want to make sure
+that the substr() or length() function works with the usually faster
+byte algorithm.
+
+Fails if the original I<UTF-X> sequence cannot be represented in the
+native 8 bit encoding. On failure dies or, if the value of I<$fail_ok> is
+true, returns false.
+
+Returns true on success.
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * C<utf8::encode($string)>
+
+Converts in-place the character sequence to the corresponding octet
+sequence in I<UTF-X>. That is, every (possibly wide) character gets
+replaced with a sequence of one or more characters that represent the
+individual I<UTF-X> bytes of the character. The UTF8 flag is turned off.
+Returns nothing.
+
+ my $a = "\x{100}"; # $a contains one character, with ord 0x100
+ utf8::encode($a); # $a contains two characters, with ords (on
+ # ASCII platforms) 0xc4 and 0x80
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * C<$success = utf8::decode($string)>
+
+Attempts to convert in-place the octet sequence encoded as I<UTF-X> to the
+corresponding character sequence. That is, it replaces each sequence of
+characters in the string whose ords represent a valid UTF-X byte
+sequence, with the corresponding single character. The UTF-8 flag is
+turned on only if the source string contains multiple-byte I<UTF-X>
+characters. If I<$string> is invalid as I<UTF-X>, returns false;
+otherwise returns true.
+
+ my $a = "\xc4\x80"; # $a contains two characters, with ords
+ # 0xc4 and 0x80
+ utf8::decode($a); # On ASCII platforms, $a contains one char,
+ # with ord 0x100. On EBCDIC platforms, $a
+ # is unchanged and the function returns FALSE.
+
+(C<"\xc4\x80"> is not a valid sequence of bytes in any UTF-8-encoded
+character(s) in the EBCDIC code pages that Perl supports, which is why the
+above example returns failure on them. What does decode into C<\x{100}>
+depends on the platform. It is C<"\x8C\x41"> in IBM-1047.)
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * C<$unicode = utf8::native_to_unicode($code_point)>
+
+(Since Perl v5.8.0)
+This takes an unsigned integer (which represents the ordinal number of a
+character (or a code point) on the platform the program is being run on) and
+returns its Unicode equivalent value. Since ASCII platforms natively use the
+Unicode code points, this function returns its input on them. On EBCDIC
+platforms it converts from EBCDIC to Unicode.
+
+A meaningless value will currently be returned if the input is not an unsigned
+integer.