mod-rewrite was on, but when I compared the current htaccess file to the pre-update back-up, I saw that the old one contained tons of data generated by our BPS Security Plugin. I turned that off, and now the permalinks work. Perhaps I should have disabled it before doing updates and I forgot…? I’ll be troubleshooting that next, but it looks like that was the source of the permalink problem in my case. Thanks for your time!