New user experience ct'd: exporting citations into LaTeX (9.5)

["Leszek Wroński" <elwro1@gmail.com>]

Guys,

thank you very much for your responses to my previous query. (I will
study the ebib package more closely; as of now it does not seem to
work with the file fields in my Mendeley-created .bib file. (Yes, I
promise will stop using Mendeley.))

I wanted to try the two LaTeX export processors mentioned in the 15.2
section of the manual: natbib and biblatex. My .org file has a
#+bibliography line specifying my .bib (which is correct, since
inserting citations is now working). I put both (use-package
oc-natbib) and (use-package oc-biblatex) in my .emacs . (I've used
natbib for years when writing .tex documents; I don't know biblatex.)

The situation is as follows:
-- if I put #+cite_export: natbib at the beginning of my .org file,
then C-c C-e l L gives me a LaTeX file which does *not* specify the
.bib file; it has \citep{} commands where they should be, but of
course bibtex doesn't know what to do with them;
-- if I use #+cite_export: biblatex instead, then the resulting .tex
file does contain the \addbibresource{} line pointing to my .bib , and
\autocite{} commands where citations should be; however, I simply
cannot get this to work: Biber works alright, but eventually pdflatex
gives me the following error:

--------------
ERROR: LaTeX3 Error: Mismatched LaTeX support files detected.

--- TeX said ---
(LaTeX3)        Loading 'l3backend-pdftex.def' aborted!
(LaTeX3)
(LaTeX3)        The L3 programming layer in the LaTeX format
(LaTeX3)        is dated 2021-01-09, but in your TeX tree the files require
(LaTeX3)        at least 2021-02-18.
---------------

which I'm unable to get rid of. (This is of course not a question for
this group but if anyone had similar problems I'd be grateful for
pointers ;-);  fmtutil-sys --all and fmtutil-user --all did nothing to
alleviate this)

So: I'd really like to keep using natbib and make it somehow insert
the information about the .bib file into the .tex when exporting. How
do I do that?

Thank you again for your help!

Best regards,

Leszek.