Samsung Galaxy S5 (SM-S902L) Firmware Overview
The archive lists 3 official builds for the Samsung Galaxy S5 across 1 region (CSC). The newest one is S902LUDUAOD3, released July 8, 2015 with Android 4.4.2.
How to Flash SM-S902L Firmware
Put the Samsung Galaxy S5 into Download Mode, load the BL, AP, CP and CSC files into Odin on a Windows PC and press Start. Pick a build with the same or a higher Bit than the one installed — a lower bootloader binary will be rejected.