From @pali

Hello, these two functions are currently marked as unstable with M in
embed.fnc function so they may change​:

Apmdb |STRLEN |sv_utf8_upgrade|NN SV *sv
Amd |STRLEN |sv_utf8_upgrade_nomg|NN SV *sv
ApdM |bool |sv_utf8_downgrade|NN SV *const sv|const bool fail_ok
Apd |void |sv_utf8_encode |NN SV *const sv
ApdM |bool |sv_utf8_decode |NN SV *const sv

These functions are available since Perl 5.6.0 (just upgrade* since
5.7.2) and used by more XS modules on CPAN. AFAIK their API or behavior
was not changed so I suggest to remove M and make them "stable".

Or is there any specific reason why upgrade and encode is without M and
downgrade and decode with M?

From @tonycoz

On Mon, 21 Jan 2019 11​:30​:41 -0800, pali@​cpan.org wrote​:

Hello, these two functions are currently marked as unstable with M in
embed.fnc function so they may change​:

Apmdb |STRLEN |sv_utf8_upgrade|NN SV *sv
Amd |STRLEN |sv_utf8_upgrade_nomg|NN SV *sv
ApdM |bool |sv_utf8_downgrade|NN SV *const sv|const bool fail_ok
Apd |void |sv_utf8_encode |NN SV *const sv
ApdM |bool |sv_utf8_decode |NN SV *const sv

These functions are available since Perl 5.6.0 (just upgrade* since
5.7.2) and used by more XS modules on CPAN. AFAIK their API or behavior
was not changed so I suggest to remove M and make them "stable".

Or is there any specific reason why upgrade and encode is without M and
downgrade and decode with M?

Done in 43c6a1a.

Tony

The RT System itself - Status changed from 'new' to 'open'

@tonycoz - Status changed from 'open' to 'pending release'

From @khwilliamson

Thank you for filing this report. You have helped make Perl better.

With the release today of Perl 5.30.0, this and 160 other issues have been
resolved.

Perl 5.30.0 may be downloaded via​:
https://metacpan.org/release/XSAWYERX/perl-5.30.0

If you find that the problem persists, feel free to reopen this ticket.

@khwilliamson - Status changed from 'pending release' to 'resolved'