This has become a common trend nowadays. New phone comes out, then an OTA update quickly follows. Sprint will be rolling out an OTA update to the Galaxy S4 simply to fix some bugs that were hiding in the device.
This update has not even been officially announced by Sprint, but users have started receiving it. This is build number L720VPUAMDL, and it is a small 30MB download. Since Sprint has not announced it yet, there is no official changelog, so your guess is as good as mine on what we can expect from it. Check your system updates to see if you have gotten it already, and let us know what you find.
Source: Android Headlines
