The Android 4.3 update for the Galaxy S4 on US Cellular is unfortunately on hold, but the carrier isn’t willing to present the same disappointment to Galaxy S III owners, and is now rolling out the 4.3 update for the device. The update carries build number R530UVXUBMJA, and brings support for the Galaxy Gear, new camera features, improved visual look, KNOX security suite, faster filesystem performance, improved RAM management, and more.
You’ll get a notification in the status bar once the update reaches your phone, though it can take a couple of days as the process is gradual. Don’t forget to do a manual check in the Settings » About phone » Software updates menu though, just in case.