On August 3rd Sprint started pushing an update to the Galaxy Note 4 that included a patch for the recently discovered “Stagefright” vulnerability. Starting on August 5th they added several more devices to the list and have announced updates for the following devices (along with the update’s build number).
The changelogs are pretty sparse but they indicate that the updates at least include a patch for Stagefright. They may include other items as well. Let us know if you find anything on your devices.