Last I heard they want to switch to another platform, and don't consider it worth upgrading to 0.19 because they're leaving soon so it wouldn't be worth the hassle.
This is pure guesswork on my part, but they could be waiting for Sublinks (a Lemmy-compatible backend) to get up to speed before switching to that. They say that the new platform is "compatible with all Lemmy apps", and Sublinks is the only project I know of that fits that criteria.
So they create a Lemmy instance.....and then decide they don't like Lemmy users. So they defederate. Then they decide THATS not enough, so they're trying to leave Lemmy entirely, but stay IN the fediverse.......but still defederated.