Yup, last night. Upvotes after the time window has expired are now recorded, but they still don't alter the point total. From a user point of view the only effect should be that you'll see the upvote arrow disappear (i.e. the standard indication that you upvoted this item). We'll see how this works for a while. If there are unintended consequences we might revert it.
We did this because users seemed to dislike being told that voting on an item was closed. Before we added that message, the software used to just silently drop votes on old items and no one complained. It was an interesting case of giving more info leading to a worse experience.