
Samsung Galaxy A3
The latest firmware for Samsung Galaxy A3 (SM-A300H) is A300HXXS1BSA1 with Android 5.0.2 (Lollipop), released on April 2, 2019 for 4 regions (CSC). Every official firmware build for SM-A300H, 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/A300HXXS1BSA1
SM-A300H started on Android 4 and has received 1 major Android upgrade; it now runs Android 5.0.2 (Lollipop). The newest build, A300HXXS1BSA1, was released on April 2, 2019. No new build has appeared for 92 months, so regular updates for this model have most likely ended.
· The security of your device has been improved.
Box codes of SM-A300H for different colors and markets. Firmware is chosen by the model code SM-A300H and your region (CSC), not by the SKU.

SM-A300XU

SM-A307GT

SM-A305YN

SM-A310X

SM-A405S
The newest firmware for SM-A300H runs Android 5.0.2 (Lollipop): build A300HXXS1BSA1, released on April 2, 2019.
The latest build for SM-A300H, A300HXXS1BSA1, was released on April 2, 2019 (7 years ago).
SM-A300H has had no new firmware for 92 months, so regular updates have most likely ended.
Yes, all firmware files for SM-A300H are 100% official, original, and obtained directly from Samsung servers.
To flash SM-A300H, 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-A300H.