probs getting latex containing xfig files to work with latex

[RalphBoland]

I believe I used Debian in 2002 though it might have been Ubuntu.
In any case I am using 32 bit Debian 10 now.
I am using a 9 year old AMD based computer but I don't believe this info in relevant.

I am updating my thesis (2002) by adding an index and fixing some typos.
My thesis contains some xfig files containing latex in the figures (for Greek
characters and subscripts).
But latex no longer accepts the (latex containing) files generated by xfig.

In order to use latex in xfig the user must generate a pair of files; either:
1) name.pdf and name.pdf_t
or
2) name.pstex and name.pstex_t.

If I go the first route and use pdflatex I first get a warning:
pdfTeX warning: pdflatex (file ./name.pdf): PDF inclusion: found PDF
version <1.7>, but at most version <1.5> allowed
Inspecting the name.pdf file verifies that it is indeed a pdf version 1.7 file.

I then get a sequence of errors such as:
! Undefined control sequence.
<argument> ... }{\mddefault }{\updefault }{\color
[rgb]{0,0,0}$Q_{5}$}}
l.14 }}}}

The errors are similar and I believe there is one per latex string usage in the xfig file.
Note: editing the name.pdf file to say version 1.5 instead of version 1.7 results
in the warning going away but the errors remain.

If I go the second route and use latex I no longer get the warning but I still get the
errors (the same errors).

I searched the Internet and found a couple of commands that were to supposed to
handle this (by telling pdftex to use pdf version 1.7 not version 1.5.
But these commands did not have any effect.

Note that I used Lyx and Libreoffice (versions released with Debian 10) to generate pdf files
and in both cases version 1.5 pdf files were generated.

So one possibility is that Xfig should be generating version 1.5 files and isn't.
Or it could be that something is wrong with my latex class file. Some changes have
been made to this file but the originalno longer works either.

Unfortunately I am not very good with Latex. My thesis (and other documents) are
written using Lyx and I work in Latex only when necessary.
The XFig files haven't been modified from the original.

I have created a tar file (150kB compressed) containing ALL the relevant files which I can
send to anyone wanting to investigate further or can post it here as an attachment if desired.
I have attempted to keep these files small so as to contain only the relevant information.
The .tex files have been generated from .lyx files but running latex/pdflatex on the .tex
files generates the same problems. The name.pdf files were generated by Lyx showing that
(incorrect) output can still be generated though I don't know how to do this using latex/pdflatex.

Any help provided much appreciated.

If this is a bug with XFig or somewhere else in Debian 10 I would appreciate it if someone
generates a bug report and posts that they have done so here. I am not sure how to do this
and in any case don't know the source of the problem.


Ralph
email: rpboland@gmail.com