At the moment I'm really annoyed about this, because trying to convert to the new look, nicknamed 'Oasis', is a nightmare. It doesn't help that the entirity of wikia's help site has been deleted and the transition guides and FAQs are useless. I'm pretty much improvising, in case you haven't noticed. But like it or not, it's upon us.
From October 6, anyone can opt-into Oasis, and by October 20 it will become default until Monaco is removed altogether on November 3.
I've been fiddling with the theme designers and features in order that everything should already work by the time it is changed over, but naturally don't expect smooth changeover. I recommend everyone opt-into Oasis on Wednesday and get used to it before you're thrown in at the deep end.
I know some others have been beta testing it aswell, here or elsewhere. If you are, do you have any suggestions about customisation, etc?