
Samsung Galaxy Alpha
The latest firmware for Samsung Galaxy Alpha (SM-G8508S) is G8508SZCS1BQD1 with Android 4.4.4 (KitKat), released on April 9, 2017 for 1 region (CSC). Every official firmware build for SM-G8508S, 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/G8508SZCS1BQD1
All 6 builds in our database run Android 4.4.4 (KitKat). The newest build, G8508SZCS1BQD1, was released on April 9, 2017. No new build has appeared for 116 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-G8508S runs Android 4.4.4 (KitKat): build G8508SZCS1BQD1, released on April 9, 2017.
The latest build for SM-G8508S, G8508SZCS1BQD1, was released on April 9, 2017 (9 years ago).
SM-G8508S has had no new firmware for 116 months, so regular updates have most likely ended.
Yes, all firmware files for SM-G8508S are 100% official, original, and obtained directly from Samsung servers.
To flash SM-G8508S, 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-G8508S.