The update is now live.
Just to clarify, the user interface is new, but the underlying network protocol still uses GameCenter. I intend to make further networking improvements in coming updates. But for the next update, it’s custom maps.
I’ve now had a few online games with the new update. Although it’s possible to find games I’m noticing that the matchmaking is far too unstable. It should just work! But it doesn’t, so I need to go to the bottom of this problem and make it top priority to really fix this.