Just in case you aren't aware, Ubuntu (Mate) 16.04 is still in the development stage and should not be used by beginners!.
If you already have 15.10 installed and like taking risks, use the following terminal command (Ctrl + Alt + t) and it will update your 15.10 to the dev version!. USE AT YOUR OWN RISK, ONCE INSTALLED THERE IS NO GOING BACK!.
