I'm updating my java project from the v.1.0.1 to the v.4.2.1...

First of all, I`ll like to know how is the correct way to update the lib itself.
Second, is there a "from -> to" list somewhere that could help me with the methods and interfaces implementations?

Or maybe the same, but from the 1.x to 2.x, that I think is where the massive differences are... It would be helpful!

Thank you in advance,