
Samsung Galaxy J1
The latest firmware for Samsung Galaxy J1 (SM-J120M) is J120MUBU2ARE1 with Android 5.1.1, released on May 3, 2018 for 8 regions (CSC). Every official firmware build for SM-J120M, 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/J120MUBU2ARE1
All 33 builds in our database run Android 5.1.1. The newest build, J120MUBU2ARE1, was released on May 3, 2018. No new build has appeared for 103 months, so regular updates for this model have most likely ended.
Specifications of SM-J120, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-J120P

SM-J110M

SM-J327VPP

SM-J320VPP

SM-J326AZ
The newest firmware for SM-J120M runs Android 5.1.1: build J120MUBU2ARE1, released on May 3, 2018.
The latest build for SM-J120M, J120MUBU2ARE1, was released on May 3, 2018 (8 years ago).
SM-J120M has had no new firmware for 103 months, so regular updates have most likely ended.
Yes, all firmware files for SM-J120M are 100% official, original, and obtained directly from Samsung servers.
To flash SM-J120M, 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-J120M.