I love many things about WordPress, but their upgrades suck. About 2 weeks ago, WP notified users that an urgent security fix was required. I put it off as long as I could, but last night seemed like a good time to try it.
I have 2--count 'em 2--test sites. I upgraded both of them with no problem. then I repeated the process exactly on my live site and permalinks broke. Anyone trying to link to one of my posts received a hideous 404 error.
Then, categories were destroyed.
Had I gone from version 1.0 to 2.3.2, I could expect issues. But I went from 2.3.1 to 2.3.2!
As i said, the WP folks do a lot of great things for free. But smooth upgrades ain't one of them.