Samsung Galaxy J7 Crown
The latest firmware for Samsung Galaxy J7 Crown (SM-S757BL) is S757BLUDS6BTE3 with Android 9, released on May 14, 2020 for 1 region (CSC). Every official firmware build for SM-S757BL, 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/S757BLUDS6BTE3
SM-S757BL started on Android 8 and has received 1 major Android upgrade; it now runs Android 9. The newest build, S757BLUDS6BTE3, was released on May 14, 2020. No new build has appeared for 78 months, so regular updates for this model have most likely ended.

SM-S741W

SM-S767VL

SM-S731U

SM-S737TL

SM-S947W
The newest firmware for SM-S757BL runs Android 9: build S757BLUDS6BTE3, released on May 14, 2020.
The latest build for SM-S757BL, S757BLUDS6BTE3, was released on May 14, 2020 (6 years ago).
SM-S757BL has had no new firmware for 78 months, so regular updates have most likely ended.
Yes, all firmware files for SM-S757BL are 100% official, original, and obtained directly from Samsung servers.
To flash SM-S757BL, 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-S757BL.