I've continued work on upgrading to Django 3 - which has turned out to be a lot more involved than originally suspected. At this point aldryn_categories and aldryn_people have both needed to be pulled into the repository tree since they're also abandoned projects that were abandoned prior to upgrading for Django 3 (though the actually changes needed in them was minimal, they won't work as-is with Django 3). Every time I've thought I was close I've discovered new problems.
One of the recurring problem I've been hitting is making sure to completely clean these as independently installed Python packages while pulling them into our source tree, though I think I have all the dependencies sorted out at this point I've learned the best policy is to wipe out all the Python packages on my test instance and reinstall them from requirements.txt.
And with this blog post my blog posts required count should return to 0, making up for the first two weeks when my administrative access needed to work on the side prevented me from posting.