
Samsung Galaxy Alpha
The latest firmware for Samsung Galaxy Alpha (SM-G850L) is G850LKLU2CVG1 with Android 5.0.2 (Lollipop), released on August 18, 2022 for 1 region (CSC). Every official firmware build for SM-G850L, 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/G850LKLU2CVG1
SM-G850L started on Android 4 and has received 1 major Android upgrade; it now runs Android 5.0.2 (Lollipop). The newest build, G850LKLU2CVG1, was released on August 18, 2022. No new build has appeared for 51 months, so regular updates for this model have most likely ended.
Specifications of SM-G850F, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-G850X

SM-G950FD

SM-G955FD

SM-G860P

SM-G750H
The newest firmware for SM-G850L runs Android 5.0.2 (Lollipop): build G850LKLU2CVG1, released on August 18, 2022.
The latest build for SM-G850L, G850LKLU2CVG1, was released on August 18, 2022 (4 years ago).
SM-G850L has had no new firmware for 51 months, so regular updates have most likely ended.
Yes, all firmware files for SM-G850L are 100% official, original, and obtained directly from Samsung servers.
To flash SM-G850L, 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-G850L.