In order to get a fixed version of another package, I need to upgrade expl3. As I am sharing this project, I’d prefer to put the new version next to the document.

I extracted the l3kernels.tds.zip in a subdirecotry l3kernels.tds/ of the directory with my document test.text, which is simply

Hello \LaTeX

but when I run it as follows, it does not work:

/tmp/test $ TEXINPUTS=./l3kernel.tds//: pdflatex test.tex
This is pdfTeX, Version 3.141592653-2.6-1.40.22 (TeX Live 2021/nixos.org) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
LaTeX2e <2021-11-15> patch level 1
L3 programming layer <2022-02-24>
Document Class: article 2021/10/04 v1.4n Standard LaTeX document class


! LaTeX3 Error: Mismatched LaTeX support files detected.
(LaTeX3)        Loading 'expl3.sty' aborted!
(LaTeX3)        The L3 programming layer in the LaTeX format
(LaTeX3)        is dated 2022-02-24, but in your TeX tree the files require
(LaTeX3)        at least 2023-02-22.

For immediate help type H <return>.

l.77      \ExplLoaderFileDate{expl3.sty}}

Should this not work? Am I misunderstanding how these .tds.zip files can be used?

  • expl3 is now part of the format, so you need to rebuild the format files. Feb 26 at 16:35
  • Sorry, but I’m a bit lost what that means. What is “the format”? I am not rebuilding anything, merely trying to use the .tds.zip file, as suggested as an easy way to upgrade expl3 in tex.stackexchange.com/a/489649/15107 Feb 26 at 16:40
  • you need to run fmtutil-sys --byfmt pdflatex (with your texinputs setting) so that the pdflatex format is rebuilt and uses the new files too. Feb 26 at 16:46
  • Hmm, I see. I fear that this may be quite annoying to get every collaborator (including those on Overleaf) to do properly. Nevertheless, thanks! Feb 26 at 16:48
  • 1
    could get difficult. siunitx really wants a newer version to use the new \codepoint_generate:nn function. Feb 26 at 17:32


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