Re: [idn] phasing out ACE

["Adam M. Costello" <idn.amc+0@nicemice.net.RemoveThisWord>]

"D. J. Bernstein" <djb@cr.yp.to> wrote:

> Suppose we do a massive redeployment of mail-displaying programs etc.
> to present IDNA names as non-ASCII glyphs.  Moving to UTF-8 then
> requires _another_ massive redeployment of those programs.

Yes, if a UTF-8 mail header standard is going to appear ever, it would
be convenient (not essential, but convenient) if it could appear soon,
so that applications would have the option of adding support for IDNA
and UTF-8 headers all at once.

> In contrast, if IDNA were modified to also require proper display of
> UTF-8

UTF-8 in what?  In UTF-8 mail headers and SMTP commands that haven't
been standardized yet?  And in upgraded HTML, HTTP, SSL, etc. standards
that haven't been created yet?  And on and on...  IDNA can't set
requirements for all these protocols, because it's way outside the scope
and expertise if this working group.

By letting IDNA out the door before we've added UTF-8 support to every
protocol, we give applications the choice of using IDNs now (and
possibly facing two upgrades), or hanging back and waiting to see if
UTF-8 versions of their protocols are forthcoming (so they can just do
one big upgrade).

AMC