
Samsung Galaxy S5 Active (DoCoMo)
The latest firmware for Samsung Galaxy S5 Active (DoCoMo) (SC-02G) is SC02GOMU2CQK4 with Android 6.0.1 (Lollipop), released on November 27, 2017 for 1 region (CSC). Every official firmware build for SC-02G, 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/SC02GOMU2CQK4
SC-02G started on Android 4 and has received 2 major Android upgrades; it now runs Android 6.0.1 (Lollipop). The newest build, SC02GOMU2CQK4, was released on November 27, 2017. No new build has appeared for 108 months, so regular updates for this model have most likely ended.

SC-02D

SC-02B

SC-01E

SC-01D

SC-01C
The newest firmware for SC-02G runs Android 6.0.1 (Lollipop): build SC02GOMU2CQK4, released on November 27, 2017.
The latest build for SC-02G, SC02GOMU2CQK4, was released on November 27, 2017 (8 years ago).
SC-02G has had no new firmware for 108 months, so regular updates have most likely ended.
Yes, all firmware files for SC-02G are 100% official, original, and obtained directly from Samsung servers.
To flash SC-02G, 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 SC-02G.