Apple released the OS X Mavericks 10.9.3 update yesterday. The big thing this update brings is improved 4K support on the Mac Pro (Late 2013) and MacBook Pro with 15-inch Retina Display (Late 2013). The update also brings iTunes 11.2, which improves podcast support and makes it more noticeable as to which podcasts you haven’t listened to yet in the Unplayed tab. Apple has also improved the Feeds tab in iTunes 11.2 making it easier to find podcasts to download and stream. iTunes 11.2 also brings many security enhancements. OS X Mavericks 10.9.3 brings various security improvements as well.
A list of the general improvements the update brings can be found here.
If you haven’t upgraded yet, you can do so through the App Store.