If I have to change the source code of an app(Email, Browser, etc) for some custom requirement, I wonder how I should maintain the changes so that I can upgrade to the newer version of the app later when it's available.
I can thinking of maintaining the diff patch and applying to the newer version later but I am wondering if there are any best practices. Is it good to just fork off a branch and keep merging the newer changes into it?
Thanks.
Sony several times described their process. Here is the links: