A few times it happens to me that I have to "reissue" a LateX document
fixing a mistake (e.g. a wrong figure included) WITHOUT altering the
original issue date.

What I do is to write "fix" inside the LateX timestamp with e.g.
\renewcommand{\today}{January 27, 2024 (fix)}

Then I run latex (tex->ps) and ps2pdf (ps->pdf)

Then use touch --reference=WrongOrOldReports/old.* new.*
to backdate the Unix timestamp.

I've noticed that the Postscript file keeps track of the REAL date e.g.
%%CreationDate: Mon Apr 15 11:18:06 2024

I wonder if also the pdf has (encoded ? I cannot find it in clear) the
actual date.

(X-post to ps and pdf NG, followup to pdf only)

LC's No-Spam Newsreading account <nospam@home.invalid> wrote or quoted:
>I wonder if also the pdf has (encoded ? I cannot find it in clear) the
>actual date.

PDF files can contain dates for several subobjects and the
whole document. For example, "14.3.3 Document Information
Dictionary" in "Document management — Portable document
format — Part 1: PDF 1.7" describes the document information
dictionary with it's "CreationDate" and "ModDate" in table 317.

Sometimes, such dates in PDFs are kind of compressed, and
one needs to use tools to render the compressed "streams"
visible, like, for example, "mutool" of "mupdf".

On 15/04/2024 12:41, LC's No-Spam Newsreading account wrote:
[...]
> I wonder if also the pdf has (encoded ? I cannot find it in clear)
> the actual date.

pdfinfo -isodates filename.pdf

This should list all the metadata including the embedded CreationDate.

Peter

On Fri, 26 Apr 2024, Peter Flynn wrote:

> pdfinfo -isodates filename.pdf

Thnaks, it does nicely !