I was just wondering if there is a simple bit of code I can put into my child theme's functions.php to change the 'Previous/Next' link on a single post page to the previous or next post within the category of the current post instead of going to the next/previous post within the entire blog?
I'm so very sorry for my late reply here. Usually we can't help with customizations, I hope you understand. By default this is not possible and unfortunately I don't know of a customization myself to change the pagination behavior.
Maybe you can find a code snippet or some further info in the WordPress Codex: https://codex.wordpress.org/Pagination
Thanks Ellen! Totally understand. I'll have a look and see what I can find.