I recently restarted and started a new map, but that's largely because the map i had before the update had the placeholder for the biome they actually added, so i wouldn't have gotten the newer biome in full on that map. If you haven't explored the affected area though you can continue using the same map (might be harder for the oceans update, you kind of have to interact with those to get anywhere). Even if you do end up needing a new map, like others mentioned, you may not need a new toon. You could always bring the established toon with all their current gear onto the new world you do end up making if it comes to that, and even swap back and forth if you need more than one trip to transfer everything you wanted.