I just downloaded season 2 chapter 7 and it gave me the option to install but not update the previous version?
You install it as a separate game. At end of S1 if you save, then close the game. Then load up S2, you should be able to load S1's save.
The previous version I'm talking about was season 2 chapter 6.
it's a brand new download. It doesnt update your previous one. your saves should be there when load it up.