
Samsung Galaxy Trend3
The latest firmware for Samsung Galaxy Trend3 (SM-G3502C) is G3502CZCUAOH1 with Android 4.3 (Jelly), released on August 23, 2015 for 1 region (CSC). Every official firmware build for SM-G3502C, 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/G3502CZCUAOH1
All 4 builds in our database run Android 4.3 (Jelly). The newest build, G3502CZCUAOH1, was released on August 23, 2015. No new build has appeared for 136 months, so regular updates for this model have most likely ended.
Specifications of SM-G350, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-G3509

SM-G3589W

SM-G357M

SM-G3568V

SM-G355M
The newest firmware for SM-G3502C runs Android 4.3 (Jelly): build G3502CZCUAOH1, released on August 23, 2015.
The latest build for SM-G3502C, G3502CZCUAOH1, was released on August 23, 2015 (11 years ago).
SM-G3502C has had no new firmware for 136 months, so regular updates have most likely ended.
Yes, all firmware files for SM-G3502C are 100% official, original, and obtained directly from Samsung servers.
To flash SM-G3502C, 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-G3502C.