I do not know. Have to checked Settings then System and System Update to check its available. I updated my box at 11.37pm last night when the now tv servers are its quietest. If an update is available on your stick update it late at night or early morning as the now servers are at it quickest as it will be less bug when updating it.
I have just updated at 3.17pm my box again to 9.3.3 build 4104.
Had my response from CS which is basically tough and coff up £25 to get a stick.
Better companies than Sky and NowTV out there so I will be off.