Tex Live update failed: dehypht-x-2023-03-06.tex not found!

[Karl Berry]

Hi Zipei - thanks for the report.

    Today I tried to update my TeX Live from version 2023 to 2024 in
    Win11 by using tlmgr update --all --self 

In general, that's not enough to upgrade between releases. Especially on
Windows, where all we can really recommend is doing a new installation.
https://tug.org/texlive/upgrade.html

However, I think the actual problem you ran into is not system-dependent.

    ! I can't find file `dehypht-x-2023-03-06.tex'.

I didn't try to reproduce, but this indicates that the language.dat file
has not been updated from the 2023 installation. As you noticed, the
<date> for the dehyph* files is different in 2024.

    However, the XeLaTeX is still broken. It seems that the formats
    remained not updated. Anyone could help?

Untested, but maybe:
  tlmgr generate language
  fmtutil-sys refresh

Or, if you run, for instance:
  kpsewhich -engine=/ uplatex.fmt
  
it should show you where the given .fmt file is. By default:
  /usr/local/texlive/2024/texmf-var/web2c/euptex/uplatex.fmt

When you ran the engines by hand, it presumably generated new .fmt
files in the current directory, and you could replace the old ones.

Hope this helps,
Karl

P.S. Norbert: do we not update the language files before remaking fmts?
I guess we'd only want to do it when relevant packages were updated. Hmm.