
Samsung Galaxy Mega 6.3
The latest firmware for Samsung Galaxy Mega 6.3 (GT-I9200) is I9200UBUDOI1 with Android 4.4.2 (KitKat), released on September 21, 2015 for 2 regions (CSC). Every official firmware build for GT-I9200, 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/I9200UBUDOI1
All 31 builds in our database run Android 4.4.2 (KitKat). The newest build, I9200UBUDOI1, was released on September 21, 2015. No new build has appeared for 135 months, so regular updates for this model have most likely ended.

GT-I9308

GT-I9268

GT-I9228

GT-I9210

GT-I9108

GT-I9103

GT-I9100T

GT-I9050
The newest firmware for GT-I9200 runs Android 4.4.2 (KitKat): build I9200UBUDOI1, released on September 21, 2015.
The latest build for GT-I9200, I9200UBUDOI1, was released on September 21, 2015 (11 years ago).
GT-I9200 has had no new firmware for 135 months, so regular updates have most likely ended.
Yes, all firmware files for GT-I9200 are 100% official, original, and obtained directly from Samsung servers.
To flash GT-I9200, 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 GT-I9200.