Originally posted by Weaver:

No updates yet to the future biomes. The next major update after H&H will be for Mistlands. Between now and then there should be regular smaller content patches. (As per the Fireside Chat video).
I'd expect things to go quicker as they've hammered out the vast majority of bugs and expanded the dev team.

Great. So If I start a new game now I should be able to continue it when Mistlands is ready