what is the highest version for xoom

Hi all

Just a quick question before i learn how to do it all.

I have a Xoom which is not been modded in any way, running 3.2 i think, the last update anyway that came from Moto.
I only use for internet browsing now and Mobdro for footy and would like to be able to cast/screen mirroring it to my new Roku 2.
So what i like to know is what is the highest version available that will enable casting/screen mirroring and will work on my Xoom.

Also is a stock version just a version from google and not a version that has been tinkered with by a developer?

many thanks in advance

problem with my xoom mz604

I did the bootloader oem unlock and the tablet didnt erase anything ? what can i do to restore my xoom i have tried everytning factory reset from android and factory reset from the recovery mode and desnt eras anything stay with the same apps and everything. help please what can i do??