iTunes 11.3 includes all-new iTunes Extras for HD movies. iTunes Extras can include behind-the-scenes videos, short films, high-resolution image galleries, director’s commentary, scenes, and more. These immersive iTunes Extras can also be enjoyed on Apple TV with Software Update 6.2 now, and will be available on iOS 8 this fall.
New iTunes Extras will be automatically added to your previously purchased HD movies as they become available—at no additional charge.
• Mac computer with an Intel processor
• To play 720p HD video, an iTunes LP, or iTunes Extras, a 2.0GHz Intel Core 2 Duo or faster processor is required
• To play 1080p HD video, a 2.4GHz Intel Core 2 Duo or faster processor and 2GB of RAM is required
• Screen resolution of 1024×768 or greater; 1280×800 or greater is required to play an iTunes LP or iTunes Extras
• Broadband Internet connection to use the iTunes Store and iTunes Extras
• Apple combo drive or SuperDrive to create audio, MP3, or back-up CDs; some non-Apple CD-RW recorders may also work
• OS X version 10.6.8 or later
• 400MB of available disk space
• iTunes in the Cloud, iTunes Match, and iTunes Radio availability may vary by country
• iTunes Radio requires OS X version 10.7 or later
• iTunes Extras requires OS X version 10.9.3 or later
iTunes 11.3.1 is available via Software Update and also as a standalone installer.
More info and download link here.