Comment 9 for bug 1771109

Which libidn2 version were you using?

I believe this has been fixed in libidn2 by now, but curl should use consider enabling Unicode TR46 from libidn2.

This is on a Ubuntu 22.04 clone (Trisquel):

jas@kaka:~$ idn2 📙.la
idn2: toAscii: string contains a disallowed character
jas@kaka:~$ idn2 -T 📙.la
xn--yt8h.la
jas@kaka:~$ curl --verbose 📙.la
* Trying 62.116.130.8:80...
* Connected to 📙.la (62.116.130.8) port 80 (#0)
> GET / HTTP/1.1
> Host: xn--yt8h.la
...