In Perl 5.30, delimiters which are unassigned code points, or which
are non-standalone graphemes will be fatal.
+=head3 In XS code, use of various macros dealing with UTF-8.
+
+These macros will require an extra parameter in Perl 5.30:
+C<isALPHANUMERIC_utf8>,
+C<isASCII_utf8>,
+C<isBLANK_utf8>,
+C<isCNTRL_utf8>,
+C<isDIGIT_utf8>,
+C<isIDFIRST_utf8>,
+C<isPSXSPC_utf8>,
+C<isSPACE_utf8>,
+C<isVERTWS_utf8>,
+C<isWORDCHAR_utf8>,
+C<isXDIGIT_utf8>,
+C<isALPHANUMERIC_LC_utf8>,
+C<isALPHA_LC_utf8>,
+C<isASCII_LC_utf8>,
+C<isBLANK_LC_utf8>,
+C<isCNTRL_LC_utf8>,
+C<isDIGIT_LC_utf8>,
+C<isGRAPH_LC_utf8>,
+C<isIDCONT_LC_utf8>,
+C<isIDFIRST_LC_utf8>,
+C<isLOWER_LC_utf8>,
+C<isPRINT_LC_utf8>,
+C<isPSXSPC_LC_utf8>,
+C<isPUNCT_LC_utf8>,
+C<isSPACE_LC_utf8>,
+C<isUPPER_LC_utf8>,
+C<isWORDCHAR_LC_utf8>,
+C<isXDIGIT_LC_utf8>,
+C<toFOLD_utf8>,
+C<toLOWER_utf8>,
+C<toTITLE_utf8>,
+and
+C<toUPPER_utf8>.
+
+There is now a macro that corresponds to each one of these, simply by
+appending C<_safe> to the name. It takes the extra parameter.
+For example, C<isDIGIT_utf8_safe> corresponds to C<isDIGIT_utf8>, but
+takes the extra parameter, and its use doesn't generate a deprecation
+warning. All are documented in L<perlapi/Character case changing> and
+L<perlapi/Character classification>.
+
+You can change to use these versions at any time, or, if you can live
+with the deprecation messages, wait until 5.30 and add the parameter to
+the existing calls, without changing the names.
=head2 Perl 5.28
are nonsensical. Using such code points with these operators
was deprecated in Perl 5.24, and will be fatal in Perl 5.28.
+=head3 In XS code, use of C<to_utf8_case()>
+
+This function is being removed; instead convert to call
+the appropriate one of:
+L<C<toFOLD_utf8_safe>|perlapi/toFOLD_utf8_safe>.
+L<C<toLOWER_utf8_safe>|perlapi/toLOWER_utf8_safe>,
+L<C<toTITLE_utf8_safe>|perlapi/toTITLE_utf8_safe>,
+or
+L<C<toUPPER_utf8_safe>|perlapi/toUPPER_utf8_safe>.
=head2 Perl 5.26