New firmware includes apps-to-SD, Samsung Knox
Update: Looks like AT&T is pushing out a similar GS4 update over-the-air.
Original story: Following the international and Sprint versions of the phone, Verizon's Galaxy S4 is today receiving a software update with a couple of significant new features. While a full changelog isn't yet available, the new "VRUAME7" firmware update seems to include apps-to-SD card support as well as Samsung's Knox security software for BYOD — both features found in the recent Sprint GS4 update. In addition, the same firmware update for the international GS4 brought improved performance, so that's something else to watch out for.
Knox in particular might be of concern to rooted users wanting to maintain superuser access to their devices, so if you're rooted you might want to hold off applying this update for the moment. Right now it seems the new firmware is only going out through Samsung's Kies desktop app, rather than over-the-air, as a hefty 1.8GB download.
Source: Android Central forums; Thanks, Jason!