Sprint has announced that the Samsung Galaxy S4 Mini devices will receive a brand new Android 4.4.2 KitKat update starting today. The new firmware upgrade comes with small fixes and several new features such as International Wi-Fi Calling Support, so you should check the notifications panel or go to System Updates and see if there are any new Android 4.4.2 files available for download.
Android 4.4.2 might possibly be the final KitKat update build released by Sprint and Samsung for the Galaxy S4 Mini, as they will most probably begin work on integrating the newly announced Android 5.0 Lollipop OS for all the other Samsung flagship devices on Sprint. This new KitKat 4.4.2 build has the firmware build set to L600VPUBNJ1 and it comes with following new features: HD Voice Icon Support, International Wi-Fi Calling Support.
This new firmware will also add various Google security patches and it should also tweak the overall Galaxy S4 Mini user interface, so that you will get the best Android 4.4.2 KitKat experience. The official changelog posted by Sprint doesn't specify if there are any other extra features nor which parts of Android 4.4.2 have been fixed in this release.
Samsung and Sprint will launch the firmware update in stages, which means that not all Galaxy S4 Mini devices on Sprint will get the new upgrade files at the same time. Don't panic in case the Android 4.4.2 KitKat L600VPUBNJ1 firmware update doesn't hit your device today, as it should arrive eventually in the following days. Note that the update is only sent for Galaxy S4 Mini devices that are running 100% stock ROMs, you will not get the firmware update in case you're currently sporting a custom ROM on your device.
When the update notification arrives you simply need to confirm the download and installation processes, then the Sprint Galaxy S4 Mini device will take care of them automatically. In case the Android 4.4.2 KitKat Update notification isn't shown by your device, then you can go to 'System Updates' menu under Settings and check manually for new firmware files availability. Tell us in comments if the update was sent your way and if you've found any major changes that aren't listed by Sprint in the changelog.