A lot of the update is going to change how progression feels with new and adjusted food at a minimum... hard to say what else may be impacted as well.

With that in mind I plan to start a new world with a new character or I won't really be able to tell the difference in the changes if I am already "progressed".

I have a bunch of old worlds I can go back to later to "update" them with new stuff, but it just makes sense to me if I want to experience fully the new stuff properly to do it with a new world and character.