Should work but it wont reset Mistlands you have already explored so if you have uncovered a large part of them you may have trouble finding what you need from the biome.

I loaded up an old map that only had 2 small areas of the Mistland's biome explored. They both contained Dvger, their buildings, mobs & new elements. The only thing missing on them was dungeons. The areas I had explored before Mistlands update were definitely not barren, simply lacking in higher end content.

What you could do, is upload your seed in the Valheim World Generator and check the discovered part of your map with the map generated at that site.

I've noticed that at some of the old maps I played at before, the boss and / or spawn locations have moved, basically changing parts of the gameplay.
I also noticed that some of the unexplored areas have turned into Mistlands, where they used to be one of the other land biomes before.

I'm not saying this will happen to you too, but it's better to be safe than sorry.


Thorin :)