Start over with a new character. Quite a lot has changed in progression that you wouldn't see if you did an old save.

For example you need turnips to upgrade the cook pot to make sausages.
Serpent stew is now locked behind iron and chain.
Comfort upgrades changed.. some items added but others were made to be replaced by the next better... for example you don't need a brazier and stone hearth just one or the other.

Mining was made a lot faster by allowing the pick to pass through so you hit everything in the swing radius. Clearing an iron crypt goes a lot faster now.

Disposal device added

Mini bosses added

New armors added, new weapons

New areas in mountains, ice caves.

Probably forgetting a lot as well.