Samsung Galaxy Note 4 users on Sprint network are getting the Android 5.0 Lollipop update right now. This will upgrade the phone firmware to version N910PVPU1BOB7.
Apart from all the new Android Lollipop features, Samsung also added Wi-Fi enhancements to the new software.
This is a staged update, means not everyone will get the update right now. You may need to wait a bit to get this new firmware. When the update will be ready for you, you will get a notification on your phone screen. But if you want to check manually, you can always do that by heading over to Settings >> About Device >> Software Update >> Update Now.
Android Lollipop brings in many new changes, including transport support for multiple accounts, improved notifications, a smoother multitasking experience, Ambient Display, smarter internet connections and the recently-announced Material Design guidelines.