Hello Calin,
I appreciate your assistance. Unfortunately the last article you posted assumes that it works as it should, but it does not. The proper authors are appearing in the post editor, but this is not displaying on the home, archive page or the post page.

So, according to your input, I have added the code prescribed on the post exactly. (Following https://forum.tagdiv.com/topic/regarding-adding-multiple-authors-on-newspaper-theme/). Pasted code into child theme function.php. Added code to loop-single-2.php and single_template_2.php which is the primary template.

Again, this did not impact the homepage, listing page, or the post page:
See staging site:
https://nondoc1dev.wpenginepowered.com/category/sports/
This page has posts attributed to guest author Jeremy Cowen in the editor:
https://nondoc1dev.wpenginepowered.com/2023/12/23/big-man-on-campus-ryan-minor-made-memories-at-ou/
This shows all posts attributed:
https://nondoc1dev.wpenginepowered.com/author/jeremy-cowen-contributor-in-chief/

I have cleared caches. Do I have any recourse?

Thank you

Hmm, I have made the prescribed modifications.

I added the code to the child functions.php file. This didn’t break things, but I can’t see that it affects anything. After adding the code to the loop-single.php and parts/single/loop-single-2.php which is the primary template we use, the post that has a guest author in the backend editor, is still displaying the #1 is still being substituted.

As co-authors/guest authors are a critical function in our site, and as the site is almost a decade of weekly news stories, changing is untenable. Without this theme update we cannot update php. Obvious problems there, including getting shut down by our hosting platform.

Can you please update your very helpful post of Jan 24, 2023 to encompass the NewsMag theme? Or what other options might we have?

Thank you very much. Does everything else in that post apply since that was written for the newspaper theme?