I just saw this update launch; I actually started playing just the day after 220.127.116.11 launched, so I was excited yet concerned to see this since I've never updated a modpack in the middle of a game. How possible is such a thing? One world generation concern I found was the buildcraft versus new oil font changes. My particular base I just moved within the past couple days to a giant wellspring of oil geysers in the desert as I prepared to pump fuel from it, so I'm sure depending on how a transition is done with this update that may need to change. Is there a need to preserve a few chunks of the current world with my base and then have the rest re-instantiate the rest of the world generation in order to generate the new world changes? I'd love to know so that I might try the new update; I definitely couldn't lose my current progress in the world though.