There is no supplemental information available for Django 3.2 versions of Build a Website with Django or Mastering Django at this time.
This is because the Django developers have again gone for a major version change (Django 3.2 to Django 4.0) without actually making any significant changes to the codebase. The Django developers did the same moving from Django 2.2 to Django 3.0.
This is good news for you, because you don’t have to do anything right now. All the code in either of the above-mentioned books will run without error on Django 4.0.
This situation can change in the future, of course. Any of you who got caught by the sudden change to pathlib in Django 3.1 can attest to that :).
If you are using a later version of Django 4, and the code from the book(s) is breaking, and there is no information on this page, contact me. I don’t work as a developer anymore, so you are likely to pick up any future bugs before I do!
All the best with your Django programming journey!
Nige