As posted here, the U.S.A. carrier minority variant, G900P, for the Sprint network, has received a security update. Still on Android 5.0 and on the same old changelist as the previous release, #4781399.
To receive update G900PVPU3BOK4 check via OTA and Samsung's Kies/Smart Switch.
I curse you crappy work Wifi and bad LTE signal! Trying to download but taking all day on the slow connection. By the time I make it across the parking lot to my car it will be downloaded.
I wonder if this security update will effect downgrading from lolipop to kitkat. I received a new sm-g900p yesterday and tried downgrading it and was unable to.