
Samsung Galaxy S6
The latest firmware for Samsung Galaxy S6 (SM-G920V) is G920VVRU4DRE1 with Android 7.0 (Lollipop), released on May 13, 2018 for 1 region (CSC). Every official firmware build for SM-G920V, 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/G920VVRU4DRE1
SM-G920V started on Android 5 and has received 2 major Android upgrades; it now runs Android 7.0 (Lollipop). The newest build, G920VVRU4DRE1, was released on May 13, 2018. No new build has appeared for 102 months, so regular updates for this model have most likely ended.
Box codes of SM-G920V for different colors and markets. Firmware is chosen by the model code SM-G920V and your region (CSC), not by the SKU.

SM-G935TZK

SM-G930AZK

SM-G935AZS

SM-G935TZS

SM-G935AZK

SM-G935TZD

SM-G975WC

SM-G975FC
The newest firmware for SM-G920V runs Android 7.0 (Lollipop): build G920VVRU4DRE1, released on May 13, 2018.
The latest build for SM-G920V, G920VVRU4DRE1, was released on May 13, 2018 (8 years ago).
SM-G920V has had no new firmware for 102 months, so regular updates have most likely ended.
Yes, all firmware files for SM-G920V are 100% official, original, and obtained directly from Samsung servers.
To flash SM-G920V, 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-G920V.