Samsung Galaxy Mega 6.3 LTE (SCH-R960) Firmware Overview
What is the latest SCH-R960 firmware?
R960TYUBPE4, released June 14, 2016 with Android 4.4.2. The archive holds 3 official builds across 1 region (CSC). Each one is the full stock ROM (flash file) for Odin, not an OTA patch.
Is the Samsung Galaxy Mega 6.3 LTE still getting updates?
Most likely not: there has been no new firmware since June 2016, so Android 4.4.2 is the last version this model got. The final builds below are still the best choice for a clean reinstall.
All SCH-R960 firmware builds
How to Flash SCH-R960 Firmware
Put the Samsung Galaxy Mega 6.3 LTE into Download Mode, load the BL, AP, CP and CSC files into Odin on a Windows PC and press Start. Use HOME_CSC to keep your data, CSC for a full wipe.