Looks like a tryout for a Seamless Branching fix. Good to see the priority it is getting.
Meant for Chinese Beta testers specifically.
Better to wait for a real update with more and confirmed fixes included.
It seems to fix playing Pixar Animations, nothing else.
The Z9S image has been made available on the Zidoo forum.
http://forum.zidoo.tv/index.php?threads/new-firmware-v2-3-17%EF%BC%88specific-bugfix-release-for-seamless-branch%EF%BC%89beta-version-for-zidoo-z9s-release.71987/