What is the last version of the book ?

[RickSanch3z]

Hello,

Recently I've downloaded .pdf version of this book from "greenteapress" site. And the version I have in my phone (downloaded some time ago) is different from the last one.
The last one has version 0.7.4 and the old .pdf I have has version 0.8.1 with some complementary information on how OS loads the program and how CPU executes the code.

I want to ask what is the last version to be focused on?

Thanks.