
Samsung Galaxy J1 Ace
Every official firmware build for SM-J110M, 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/J110MUBS0ASA1
Specifications of SM-J110, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-J110L

SM-J100VPP

SM-J120A

SM-J210F

SM-J106M
You can find the firmware on the model: SM-J110M page.
Yes, all firmware files for SM-J110M are 100% official, original, and obtained directly from Samsung servers.
To flash SM-J110M, 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-J110M.