Due to medical reasons (crushed disk between c2 & c3) I haven't played in a year. Now that I can use my hands again I can try to play again. The question I have is, do I have to start a new world for all the new stuff to work?
I could be wrong but i don’t think so. The only time i had difficulty with a new expansion and had to start over was when i had built in the Ashlands before the expansion was released. For some reason it caused some land glitching and i decided i wanted to start over. But even then I really didn’t have to because the glitching effects were localized and so as long as you didn’t build up in any areas that hadn’t been finished you should be fine. Again, i could be wrong and would love to hear what more knowledgeable people would say.
You can continue on your old world, as far as I know. If you have discovered the new biomes (e.g. mistlands or ashlands) there already, there yould be some version issues. Newly discovered biomes will behave as they should do accordingto the new version.