chipset security enhancement rocks your world. This update is actually designed to close the Exynos exploit that was discovered on Samsung devices running the Samsung Exynos 4210 or Samsung Exynos 4412 processor. With the exploit, any app installed on the phone could be used to gain access to that device, allowing someone with evil intent to wipe the memory or brick your device.
Before updating the phone, make sure that you have an active SIM card in the unit and that you have a full battery ready. If you don't want to wait for the OTA update to arrive, you can manually check to see if it is on your phone by going to Settings > About device> Software update > Check for Updates.
source: AT&T via AndroidAuthority