Originally posted by Dr.Moriarty:

Can I keep my world and discover mistlands?

Yes, but you may want to consider starting over anyway. As mentioned, you'll be able to discover mistlands fine. However, the Mistlands update also changes the map generation, making the landmass sizes and shapes different. Starting over will get you a new world seed that has the new landmass system.

Unless you spent the entire weekend building a castle, I'd say it's best to make a new map and have your character log into that one. You can make as many trips as you like to take your stuff over. But since it's only been a weekend, I assume that it's not a whole lot of stuff. Just put some chests down in the new world and go back and forth until you have all the important things and resources moved.

You can keep your world, and it might be fine. Sail east or west to find larger mistland areas. But some players, not all, had trouble with the terrain on old maps when it was on test server.

If you didn't discover any mistlands you're fine. Their features have not been built yet on your save.

Only mistland biomes on saves that *previously* discovered those areas are botched. Any undiscovered/fog-of-war land not yet touched is safe.