
The latest firmware for GT-N5100 is N5100XXDNL5 with Android 4.4.4 (KitKat), released on December 26, 2014 for 1 region (CSC). Every official firmware build for GT-N5100, 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/N5100XXDNL5
All 30 builds in our database run Android 4.4.4 (KitKat). The newest build, N5100XXDNL5, was released on December 26, 2014. No new build has appeared for 144 months, so regular updates for this model have most likely ended.

GT-N7000B

GT-N5105

GT-N8020

GT-N8013

GT-N8005
The newest firmware for GT-N5100 runs Android 4.4.4 (KitKat): build N5100XXDNL5, released on December 26, 2014.
The latest build for GT-N5100, N5100XXDNL5, was released on December 26, 2014 (11 years ago).
GT-N5100 has had no new firmware for 144 months, so regular updates have most likely ended.
Yes, all firmware files for GT-N5100 are 100% official, original, and obtained directly from Samsung servers.
To flash GT-N5100, 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-N5100.