After one too many PHP error messages in the middle of content, and too many too many failures to connect from the CDN (probably related) when trying to publish posts, I sought to put the next version of the blog software on, even if still beta.
It wasn't beta!
The upgrade hiccuped a couple of times because of file permissions, but went smoothly with those corrections. I've not checked out any of the new features or other changes, but at least the PHP errors have gone.
Let's see if publishing is fixed.