
Samsung Galaxy Note5
The latest firmware for Samsung Galaxy Note5 (SM-N920R4) is N920R4TYS3CRJ1 with Android 7.0 (Nougat), released on September 30, 2018 for 1 region (CSC). Every official firmware build for SM-N920R4, 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/N920R4TYS3CRJ1
SM-N920R4 started on Android 5 and has received 2 major Android upgrades; it now runs Android 7.0 (Nougat). The newest build, N920R4TYS3CRJ1, was released on September 30, 2018. No new build has appeared for 98 months, so regular updates for this model have most likely ended.
Specifications of SM-N920, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-N920AZW

SM-N930V

SM-N910V

SM-N915V

SM-N916S
The newest firmware for SM-N920R4 runs Android 7.0 (Nougat): build N920R4TYS3CRJ1, released on September 30, 2018.
The latest build for SM-N920R4, N920R4TYS3CRJ1, was released on September 30, 2018 (8 years ago).
SM-N920R4 has had no new firmware for 98 months, so regular updates have most likely ended.
Yes, all firmware files for SM-N920R4 are 100% official, original, and obtained directly from Samsung servers.
To flash SM-N920R4, 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-N920R4.