This system informed me that an automatic update (3.8.1) has been installed on this system.
Whether you like it or not, this is kind of a killer feature that takes care of one of the biggest problems out there in the WP world: out-of-date systems. There are all kinds of people running WordPress, and not all of them are keeping as close an eye on their installations as they might. These automatic upgrade go a long way toward keeping those systems safe.
If you’re the kind of person who’s really on top of things, this might be welcome, or an annoyance. But there are more people than you know who just aren’t getting in there and doing the updates when they should.