I needed to fix comments here, so I had a few choices. a) Figure out what was wrong, or b) just upgrade and let that fix it.
I upgraded. That fixed it.
As a downside, I no longer have the comment validation plugin. Someone should write a plugin that parses all input as HTML 5 and re-serializes it as valid whatever-language-you’re-using.
Edit: And let the blogspam begin! I’m holding all comments for moderation now. I think you can get around that by registering an account here or something (?) but I basically don’t care yet. Maybe I’ll look into it once I actually understand enough PHP to make changes.