It is indeed the old IFE but I wouldn't worry about it being slow or a poor quality screen, i'd worry about it working at all. Flying the route back in Club a few weeks ago I had a hissing sound so bad you could hear it from the aisle( I was in a window seat) and Mrs Clam had a menu on her screen that wouldn't go away so neither of us had useable IFE at all for the 12.5hr flight. CC reset the row 3 times and the CSM was excellent submitting a complaint via her ipad but i'd strongly advise preloading content onto your phone or tablet to be safe. If they haven't bothered updating J then I'd doubt they have improved the WT+ offering even though it is a newer product.

FYI getting to the airport can be a bit horrific traffic wise( even outside rush hour) so i'd factor in some extra time. If taking a cab to/ from the airport then have some COIN/ small note change to hand as you are expected to pay for the numerous tolls( it's a thing, they aren't ripping you off asking you to pay)Use the premium security up one floor it makes a BIG difference and the CX lounge there is tucked away under a set of escalators by the C gates with no real indication you need to turn around at the bottom to find it. When you get there expect to fight for a seat as it's appallingly overcrowded. ( not sure if you have Status to get you in the lounge). On the upside the bartenders will pour you a very good measure if you say you want a large so that's something.

Not trying to put a downer on things but imo better to know these things and be prepared.