
Samsung Galaxy J3(2017)
The latest firmware for Samsung Galaxy J3(2017) (SM-J330L) is J330LKLU6CUD1 with Android 9 (Pie), released on May 17, 2021 for 1 region (CSC). Every official firmware build for SM-J330L, 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/J330LKLU6CUD1
SM-J330L started on Android 7 and has received 2 major Android upgrades; it now runs Android 9 (Pie). The newest build, J330LKLU6CUD1, was released on May 17, 2021. No new build has appeared for 66 months, so regular updates for this model have most likely ended.
Specifications of SM-J330, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-J330N

SM-J337A

SM-J327VPP

SM-J320VPP

SM-J326AZ
The newest firmware for SM-J330L runs Android 9 (Pie): build J330LKLU6CUD1, released on May 17, 2021.
The latest build for SM-J330L, J330LKLU6CUD1, was released on May 17, 2021 (5 years ago).
SM-J330L has had no new firmware for 66 months, so regular updates have most likely ended.
Yes, all firmware files for SM-J330L are 100% official, original, and obtained directly from Samsung servers.
To flash SM-J330L, 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-J330L.