My rough notes for this meeting have been posted to the WG21 wiki (here
<https://wiki.edg.com/bin/view/Wg21telecons2025/SG16Teleconference2025-06-11>)
and the related github tracking issues updated (CWG 2843
<https://github.com/cplusplus/papers/issues/1736>, P3717R0
<https://github.com/cplusplus/papers/issues/2344>; there is no github
tracker issue for P3727 yet).

Tom.

On 6/10/25 3:28 AM, Tom Honermann via SG16 wrote:
>
> SG16 will hold a meeting on Wednesday, June 11th, at 19:30 UTC
> (timezone conversion
> <https://www.timeanddate.com/worldclock/converter.html?iso=20250611T193000&p1=1440&p2=tz_pdt&p3=tz_mdt&p4=tz_cdt&p5=tz_edt&p6=tz_cest>).
>
> If you need a .ics file to import into your calendar, you can download
> it here
> <https://documents.isocpp.org/remote.php/dav/public-calendars/R7imgS2LJD9xfeWN/94A3D3A0-70B9-4847-935F-9453DB2BB216.ics?export>.
>
> The agenda follows.
>
> * CWG2843: Undated reference to Unicode makes C++ a moving target
> <https://cplusplus.github.io/CWG/issues/2843.html>.
> * D3727R0: Update Annex E onto Unicode 15.1
> <https://isocpp.org/files/papers/D3727R0.pdf>.
> * P3717R0: Update Annex E onto Unicode 16 <https://wg21.link/p3717r0>.
>
> SG16 previously reviewed *CWG2843* during the 2024-01-10
> <https://github.com/sg16-unicode/sg16-meetings/blob/master/README-2024.md#january-10th-2024>,
> 2024-02-07
> <https://github.com/sg16-unicode/sg16-meetings/blob/master/README-2024.md#february-7th-2024>,
> and 2024-02-21
> <https://github.com/sg16-unicode/sg16-meetings/blob/master/README-2024.md#february-21st-2024>
> SG16 meetings. Those meetings culminated in consensus to specify
> Unicode 15.1 as the minimum version for C++26 (and C++23 as a DR) with
> an allowance for use of a more recent Unicode version in conforming
> implementations. EWG confirmed this direction during its 2024-03
> in-person meeting in Tokyo
> <https://wiki.edg.com/bin/view/Wg21tokyo2024/NotesEWGCWG2843>. Since
> then, the issue has been awaiting proposed wording that includes an
> update to the non-normative content of annex E. Steve recently
> published *P3717R0* with the minimal wording needed to update annex E,
> but with additional scope to bump the minimum Unicode version to 16.
> Push back on the additional Unicode version change lead Jens to update
> the proposed resolution in CWG2843 (see the "Additional notes (May,
> 2025)" section) to apply the minimal update to annex E. Meanwhile,
> Steve authored *D3727R0* which retains the Unicode 15.1 direction
> already approved by EWG, but with additional suggested updates for
> annex E that go beyond the minimum strictly necessary to resolve
> CWG2843; see related discussion on the SG16 mailing list
> <https://lists.isocpp.org/sg16/2025/05/4581.php> and in particular,
> Robin Leroy's comments
> <https://lists.isocpp.org/sg16/2025/06/4584.php> that motivated the
> additional changes. The goal of this meeting will be to:
>
> 1. Determine the minimum Unicode version to recommend as the
> normative reference in the C++ standard with acknowledgment of the
> following:
> 1. EWG has already approved Unicode 15.1 as a DR for C++23.
> 2. A recommendation to move to Unicode 16 will require an audit
> to address impact from the rebase, approval from EWG, and,
> presumably, divergence from C++23 since updating C++23 to
> depend on a standard that had not yet been published when
> C++23 was published would be ill-advised. Note that no
> features added to C++26 depend on Unicode 16.
> 2. Determine the scope of changes to make to annex E:
> 1. The minimal change needed to resolve CWG2843 (the removal of
> [uaxid.def.rfmt] <https://eel.is/c++draft/uaxid#def.rfmt> as
> in the May 2025 proposed resolution in CWG2843), or
> 2. The larger set of changes as proposed in D3727R0 (possibly
> with additional refinement per discussion on the SG16 mailing
> list and any further discussion).
>
> I haven't scheduled any other papers or topics for this meeting so as
> to maximize our chances of reaching a final consensus on this issue.
>
> *Steve, Robin, and Jens*: it would be great if the three of you could
> collaborate to reach agreement on a unified proposal prior to this
> meeting (I recognize time is short to do so).
>
> Tom.
>
>