From the Worlds Adrift blog, they've apparently heard back from the Unity side:

"Bossa has been informed by Unity that Worlds Adrift should not be affected by the situation between Improbable and Unity. Thus, Worlds Adrift remains live as normal."

You should play it while you can. It's a very fun game and the PVE server is some of the best relaxing gameplay I have experienced (as long as falling into an abyss doesn't stress you out)

Worlds Adrift says they're still up for now.

that remains to be seen for how long. if they are operating against the Unity ToS, I would expect it to be down soon as a result.

Like I said, I really hope they get this fixed, because that game looked good.