The 'new' IFE, AVOD StudioCX, the WORKS etc... in Business and First Class ... will only be available on aircrafts that have the new Business Class seats.

When each aircraft goes in for NBC reconfiguration, the entire StudioCX is overhauled in First and Business Class. The video8 personal player is removed in First and seats are reconfigured to have in seat power supply and Tenzing outlets too.

So right now, with only half of the 747s configured, you may still be stuck carrying extra batteries about as we don't know which aircraft will be flying which route!