
Samsung GALAXY S4
The latest firmware for Samsung GALAXY S4 (SPH-L720T) is L720TVPUCOK3 with Android 5.0.1 (KitKat), released on November 17, 2015 for 3 regions (CSC). Every official firmware build for SPH-L720T, newest first: one row per build with all regions (CSC) that received it.
Each firmware build has its own page at https://samfirm.shop/build/{PDA}, where {PDA} is the build number from the list above. Example: https://samfirm.shop/build/L720TVPUCOK3
SPH-L720T started on Android 4 and has received 1 major Android upgrade; it now runs Android 5.0.1 (KitKat). The newest build, L720TVPUCOK3, was released on November 17, 2015. No new build has appeared for 133 months, so regular updates for this model have most likely ended.

SPH-M840

SPH-L900

SPH-L710T

SPH-L720

SPH-L600
The newest firmware for SPH-L720T runs Android 5.0.1 (KitKat): build L720TVPUCOK3, released on November 17, 2015.
The latest build for SPH-L720T, L720TVPUCOK3, was released on November 17, 2015 (10 years ago).
SPH-L720T has had no new firmware for 133 months, so regular updates have most likely ended.
Yes, all firmware files for SPH-L720T are 100% official, original, and obtained directly from Samsung servers.
To flash SPH-L720T, you need to download the appropriate firmware, put your device into Download Mode, and use the Odin tool to load the BL, AP, CP, and CSC files.
Downgrading is only possible if the bootloader version (binary bit) of the old firmware matches the current one. Always check the binary version before flashing SPH-L720T.