While the Galaxy Note 4 is going on being 3 years old now, Sprint nor Samsung have left their users in the dust. The Galaxy Note 4 on Sprint is receiving the latest security update right now, even ahead of some of their newer flagship smartphones. The Galaxy Note 4 is getting an update to bring it to build N910PVPS4DQC1, which includes the March 2017 security update and it weighs in at about 333MB in size. So it is a fairly large update to the Galaxy Note 4, although that is to be expected, especially since there are some other fixes included here, and not just the security update.
Those with the Galaxy Note 4 on Sprint should begin receiving this update over the next few days. It's rolling out as a staged roll out, so some may see the update available today, while others may need to wait a few days. But you can grab the update by heading to Settings, and then tapping on About Phone and Check for Updates. You'll want to be sure that you are on Wi-Fi before attempting to download this update, as it'll be faster and use less of your battery. You'll also want to make sure that you have at least 50% charge on your battery before attempting the update. Just in case it takes longer to install than it normally would. This way your Galaxy Note 4 doesn't die in the middle of the update, which could be catastrophic.
The Galaxy Note 4 was released in the fall of 2014, and was actually Samsung's last smartphone to feature a removable battery. Seeing as how shortly after that, the company moved from the plastic build for their smartphones, to metal and glass with the Galaxy S6 in 2015. The Galaxy Note 4 has remained popular because it has a removable battery, a feature that many power users prefer, and at this point, there are no new smartphones with a removable battery, as they have all opted for a non-removable one. Including LG, who was the last hold out, with the LG G6 getting a non-removable battery too. You can check out the notes for this update to the Galaxy Note 4 by hitting the source link below.