Wow, the gang just looks... old.
Some more than others. I like what Rimmer is doing with his hair this season. It gives a certain dignity to his age that his short, curly, receding hairline couldn't quite muster. Kryten seems a bit older but the prosthetics are hiding a lot of that. Lister looks a bit older from some angles but not so much from others. And Cat hardly looks older at all.
But what I love best is that the show seems to have recaptured the look & feel of the old series in a way that the single-camera, no-laugh-track "Back to Earth" just couldn't.