There are about 40 consoles out there with V.1 firmware so this really only concerns them, every kit/console from now on will have V.2 firmware.
The update fixes problems with mmc5 games like castlevania 3, Everdrive N8, FDS, saving scanlines settings, adds 4x height in 1080p to fix scanlines, the diagnostic LED flashes differently, and a couple audio levels are preset lower.
From Twitter:
@krikzz
#EverDrive N8 OS v13. Now compatible with NES HDMI adapter!
A huge thanks to Chris for helping with this renovation!