
The latest firmware for GT-P3100 is P3100XXDMG6 with Android 4.2.2 (Jelly Bean), released on August 2, 2013 for 1 region (CSC). Every official firmware build for GT-P3100, 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/P3100XXDMG6
All 38 builds in our database run Android 4.2.2 (Jelly Bean). The newest build, P3100XXDMG6, was released on August 2, 2013. No new build has appeared for 161 months, so regular updates for this model have most likely ended.
Box codes of GT-P3100 for different colors and markets. Firmware is chosen by the model code GT-P3100 and your region (CSC), not by the SKU.

GT-P6810

GT-P6211

GT-P6200

GT-P1000N

GT-P7320T
The newest firmware for GT-P3100 runs Android 4.2.2 (Jelly Bean): build P3100XXDMG6, released on August 2, 2013.
The latest build for GT-P3100, P3100XXDMG6, was released on August 2, 2013 (13 years ago).
GT-P3100 has had no new firmware for 161 months, so regular updates have most likely ended.
Yes, all firmware files for GT-P3100 are 100% official, original, and obtained directly from Samsung servers.
To flash GT-P3100, 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 GT-P3100.