
Samsung Galaxy Tab3 8.0
The latest firmware for Samsung Galaxy Tab3 8.0 (SM-T315) is T315XXUBPA3 with Android 4.4.2 (KitKat), released on January 17, 2016 for 1 region (CSC). Every official firmware build for SM-T315, 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/T315XXUBPA3
All 27 builds in our database run Android 4.4.2 (KitKat). The newest build, T315XXUBPA3, was released on January 17, 2016. No new build has appeared for 131 months, so regular updates for this model have most likely ended.
Box codes of SM-T315 for different colors and markets. Firmware is chosen by the model code SM-T315 and your region (CSC), not by the SKU.

SM-T315T

SM-T310

SM-T210L

SM-T320X

SM-T321
The newest firmware for SM-T315 runs Android 4.4.2 (KitKat): build T315XXUBPA3, released on January 17, 2016.
The latest build for SM-T315, T315XXUBPA3, was released on January 17, 2016 (10 years ago).
SM-T315 has had no new firmware for 131 months, so regular updates have most likely ended.
Yes, all firmware files for SM-T315 are 100% official, original, and obtained directly from Samsung servers.
To flash SM-T315, 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-T315.