
Samsung GALAXY Tab 3 Lite 3G
Every official firmware build for SM-T111NQ, 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/T111NQXXUAOC1
Specifications of SM-T111N, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-T111M

SM-T116NY

SM-T113NU

SM-T210X

SM-T217T
You can find the firmware on the model: SM-T111NQ page.
Yes, all firmware files for SM-T111NQ are 100% official, original, and obtained directly from Samsung servers.
To flash SM-T111NQ, 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-T111NQ.