On 28/07/2023 15:28, Thierry wrote: > Yes. But the same engine does things differently between LaTeX > 2022-11-01 and LaTeX 2023-06-01. > > So could someone give me the diff of the input related things in > LaTeX between these two versions so that I can have a clue about > what LaTeX is expecting and what it is eventually calling (because it > could be calling, low level, the open routine, and there is no > acrobatics made in the open routine in kerTeX: the handling is made > before calling the routine; so if LaTeX is calling low level like > this, the result is not a surprise). Older LaTeX used \openin + \ifeof to test for file existence; we now use \(pdf)filesize, which is expandable and reports "0" for a non-existent file. Both methods should find "foo.tex" from "foo" in the same way. Joseph