
Samsung Galaxy J5
The latest firmware for Samsung Galaxy J5 (SM-J500Y) is J500YXXU1BQI1 with Android 6.0.1 (Lollipop), released on September 11, 2017 for 1 region (CSC). Every official firmware build for SM-J500Y, 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/J500YXXU1BQI1
SM-J500Y started on Android 5 and has received 1 major Android upgrade; it now runs Android 6.0.1 (Lollipop). The newest build, J500YXXU1BQI1, was released on September 11, 2017. No new build has appeared for 111 months, so regular updates for this model have most likely ended.
Specifications of SM-J500, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-J500N0

SM-J510UN

SM-J600N

SM-J400M

SM-J700T1
The newest firmware for SM-J500Y runs Android 6.0.1 (Lollipop): build J500YXXU1BQI1, released on September 11, 2017.
The latest build for SM-J500Y, J500YXXU1BQI1, was released on September 11, 2017 (9 years ago).
SM-J500Y has had no new firmware for 111 months, so regular updates have most likely ended.
Yes, all firmware files for SM-J500Y are 100% official, original, and obtained directly from Samsung servers.
To flash SM-J500Y, 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-J500Y.