updated 12:03 pm EDT, Thu July 10, 2014
iOS users will have to wait for iOS 8
Apple has released iTunes 11.3 for Mac and Windows users. The main addition is support for iTunes Extras associated with HD movies, granting access to things like galleries, commentaries, behind-the-scenes clips, and short films. Not every movie has Extras, since these require special formatting on the part of content creators, but even previously-purchased titles can get Extras for free if they're added later.
Extras should now also be accessible to Apple TV owners. In that circumstance, people must be running the v6.2 firmware released last month. Extras will also eventually make their way to iOS, but Apple says that users will have to wait for iOS 8.
iTunes 11.3 can be downloaded via the Mac App Store, Apple's website, or the Software Update tool for Windows.