The Samsung Galaxy S4 on Sprint has started receiving the Android 4.3 Jelly Bean software update. Verizon was the first carrier to update the phone in the U.S. on Monday and that leaves both the AT&T and T-Mobile branded Galaxy S4 models left to receive the updated version of Android.Along with the new features and improvements from Android 4.3, users will also get the advantage of the latest Samsung Premium Suite, which includes support for the Samsung Galaxy Gear smartwatch and adds support for Samsung KNOX to the device. Samsung's KNOX is designed for those who bring their device to the workplace, pressing KNOX opens up a "secure container" that includes a browser, your contacts and calendar enabling you to do work-related chores without fear of a security breach. When you're done, click on the KNOX icon to turn it off.
Based on available information AT&T customers should receive the update on November 13th with the T-Mobile branded model receiving the Suite on November 18th.
source - Android Central