The Samsung Galaxy Note 4 is now receiving the December security patch from Sprint. It was only last week that T-Mobile pushed out the December patch for the Note 4. The update brings device stability and performance improvements, bug fixes and adds other new and enhanced features too.
Before updating your Note 4, make sure that your device is charged to at least 50% and that you also have a stable network connection, preferably WiFi. Also, ensure that your device is decrypted before updating, in case you had encrypted your smartphone before.
The Note 4 is unfortunately not in line for the update to Nougat. But it isn’t impossible to get Nougat running on the Note 4, with the trick being that you could try Nougat through custom ROMs. But be advised, rooting and flashing custom ROMs onto your device will void warranty and the ROMs may come with a few bugs too.