
Samsung GALAXY MEGA
The latest firmware for Samsung GALAXY MEGA (SHV-E310S) is E310SKSUBQA1 with Android 4.4.2 (KitKat), released on January 2, 2017 for 1 region (CSC). Every official firmware build for SHV-E310S, 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/E310SKSUBQA1
All 6 builds in our database run Android 4.4.2 (KitKat). The newest build, E310SKSUBQA1, was released on January 2, 2017. No new build has appeared for 119 months, so regular updates for this model have most likely ended.

SHV-E500L

SHV-E400K

SHV-E370K

SHV-E330L

SHV-E310L
The newest firmware for SHV-E310S runs Android 4.4.2 (KitKat): build E310SKSUBQA1, released on January 2, 2017.
The latest build for SHV-E310S, E310SKSUBQA1, was released on January 2, 2017 (9 years ago).
SHV-E310S has had no new firmware for 119 months, so regular updates have most likely ended.
Yes, all firmware files for SHV-E310S are 100% official, original, and obtained directly from Samsung servers.
To flash SHV-E310S, 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 SHV-E310S.