An oft-requested feature on e2 since the beginning of time is the ability to recast votes on writeups. After much debate and discussion over the implementation, it is finally enabled, but only for changing a downvote to an upvote. The recipient of a flipped vote will receive the XP previously denied by the downvote, but the voter should not receive any GP for a recast vote.
Use your votes carefully. This is largely meant to encourage people to improve writeups in order to convert downvotes to upvotes.
One technical note: we had two conflicting implementations of quickvoting, so I eliminated one of them. If your quickvote buttons are suddenly disabled by this change, head over to user settings to enable them again (the quickvote tickbox).
As usual, report bugs to e2 bugs as you encounter them, or simple ideas for improvement to suggestions for e2.