Compare two builds and create update file

Hi, I just finished creating a huge update for my game. and I know that some players don't want to bother with redownloading the whole game again

So I would like to create an update file that allows players to update from one version to the other

Now I have the old version's build and the new version's build on my PC. and I would like to compare the builds to see what changed and create an update file that only contains the changes required to go from one version to another.

Now how do I do that?