pdf-version not allowed

[Reinhard Kotucha]

On 2023-03-27 at 15:23:01 +0200, bernhard kleine wrote:

 > After installing texlive2023 I got the following error message:
 > 
 > pdfTeX warning: pdflatex.exe (file f:/Meine
 > Noten/EigeneNoten/Bruckner/Bruckner
 > _Choralmesse_für_den_Gründonnerstag_WAB9_Titelblatt.pdf): PDF inclusion:
 > foun
 > d PDF version <1.7>, but at most version <1.5> allowed
 > 
 > texlive2022 didnot show such an error.

First of all, it's a warning, not an error message.  It's important to
distinguish between errors and warnings.

Secondly, nothing changed regarding this message in TeX Live 2023,
I've seen these messages with previous releases many times.  Maybe
you've overseen them in the past.

The best you can do is to ignore the warning message.  If it annoys
you, just open the file 'Bruckner...Titelblatt.pdf' with a text editor
which doesn't mangle binary files and replace the very first line

   %PDF-1.7

by

   %PDF-1.5

and the warnings will disappear.  Avoid editors from Microsoft, they
probably try to "repair" line breaks and thus break binary files.

I don't recommend to increase the PDF version number of the document
you create.  This postpones the problem to programs processing your
file.

PDF is an extensible file format.  Whenever it was extended the
version number of the specification was increased.

But what you actually do here is to extract the content of a page
object from an external PDF file.  This worked from the beginning,
regardless which other features beyond PDF-1.0 are used in that file.

Hence it's absolutely safe to ignore the warnings.

IMO the best solution is to remove these warning messages from pdftex
and luatex because they are, as far as I can see, unnecessary and
misleading.  The comment at the top of an external PDF file has no
impact on PDF page object extraction in any way.  pdftex and luatex
always do the right thing.

Regards,
  Reinhard

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Reinhard Kotucha                            Phone: +49-511-3373112
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