The Xperia Z3v is the Z3 with Verizon branding. Since the logo alone isn't enough to keep customers happy, the carrier also provides them with the largest network in the US and occasional over-the-air updates. Currently it's pushing out an OTA that hits the Sony flagship with a number of enhancements.
The standout item on the changelog, if you're into Play Movies, is the ability to stream in HD. This is the way video was meant to be consumed on the device's 5.2-inch 1920 by 1080 display.
Other tweaks include improving NFC performance, reducing mobile data notifications during calls, and disabling HTML links in email. A couple center on Sony's Lifelog app, such as changing default height and weight measurements to standard along with providing new text to guide users through the process of putting their device into high accuracy mode.
For the full list of changes, hit up the source link below.