
Samsung Galaxy A5
The latest firmware for Samsung Galaxy A5 (SM-A500L) is A500LKLU1CQC1 with Android 6.0.1 (Marshmallow), released on March 1, 2017 for 1 region (CSC). Every official firmware build for SM-A500L, 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/A500LKLU1CQC1
SM-A500L started on Android 4 and has received 2 major Android upgrades; it now runs Android 6.0.1 (Marshmallow). The newest build, A500LKLU1CQC1, was released on March 1, 2017. No new build has appeared for 117 months, so regular updates for this model have most likely ended.
Specifications of SM-A500F, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-A500X

SM-A507FN

SM-A505YN

SM-A600A

SM-A515X
The newest firmware for SM-A500L runs Android 6.0.1 (Marshmallow): build A500LKLU1CQC1, released on March 1, 2017.
The latest build for SM-A500L, A500LKLU1CQC1, was released on March 1, 2017 (9 years ago).
SM-A500L has had no new firmware for 117 months, so regular updates have most likely ended.
Yes, all firmware files for SM-A500L are 100% official, original, and obtained directly from Samsung servers.
To flash SM-A500L, 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-A500L.