
Samsung Galaxy Tab S3
Every official firmware build for SM-T825X, newest first: one row per build with all regions (CSC) that received it.
Box codes of SM-T825X for different colors and markets. Firmware is chosen by the model code SM-T825X and your region (CSC), not by the SKU.

SM-T825N0

SM-T727A

SM-T837A

SM-T810X

SM-T818V
You can find the firmware on the model: SM-T825X page.
Yes, all firmware files for SM-T825X are 100% official, original, and obtained directly from Samsung servers.
To flash SM-T825X, 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 SM-T825X.