
The latest firmware for GT-P5100 is P5100XXDNA1 with Android 4.2.2 (Jelly Bean), released on January 3, 2014 for 22 regions (CSC). Every official firmware build for GT-P5100, 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/P5100XXDNA1
All 39 builds in our database run Android 4.2.2 (Jelly Bean). The newest build, P5100XXDNA1, was released on January 3, 2014. No new build has appeared for 155 months, so regular updates for this model have most likely ended.

GT-P6810

GT-P6211

GT-P6200

GT-P1000N

GT-P7320T
The newest firmware for GT-P5100 runs Android 4.2.2 (Jelly Bean): build P5100XXDNA1, released on January 3, 2014.
The latest build for GT-P5100, P5100XXDNA1, was released on January 3, 2014 (12 years ago).
GT-P5100 has had no new firmware for 155 months, so regular updates have most likely ended.
Yes, all firmware files for GT-P5100 are 100% official, original, and obtained directly from Samsung servers.
To flash GT-P5100, 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-P5100.