
Samsung Galaxy Tab S10+, 256 GB, Moonstone Gray
Every official firmware build for SM-X820N, newest first: one row per build with all regions (CSC) that received it.
Box codes of SM-X820N for different colors and markets. Firmware is chosen by the model code SM-X820N and your region (CSC), not by the SKU.

SM-X820

SM-X826N

SM-X810N

SM-X926N

SM-X920
You can find the firmware on the model: SM-X820N page.
Yes, all firmware files for SM-X820N are 100% official, original, and obtained directly from Samsung servers.
To flash SM-X820N, 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-X820N.