I am probably outliner but I really didn't get the book at all. There is much intensive talk about differences between every version from 2.0 to 5.0, how you d

I am probably outliner but I really didn't get the book at all. There is much intensive talk about differences between every version from 2.0 to 5.0, how you do same thing in 2.0, then in 3.0, 4.0 and 5.0. I really don't get why I would need to know the difference between them unless my job involves maintaining super old systems. (Which is quite common). However for me personally it was not a good book at all because for me personally that information was completely useless.