After some of its bigger cousins sent out Lollipop updates for the Galaxy S4, now US Cellular is doing the same. This is Android 5.0, with a new version number of R970TYUGOE2.
As is typical with Samsung Galaxy devices, you can either download the update OTA or through Samsung Kies on your computer.
Since this is the Galaxy S4 and it is a nearly two-year-old device, this is likely the last major update that it will get. So go ahead and enjoy it US Cellular customers.