Thanks for the explanation. I think you can use the files stored on the system itself in many cases, at least for binaries. /etc/ and other configuration is an

Thanks for the explanation. I think you can use the files stored on the system itself in many cases, at least for binaries. /etc/ and other configuration is an exception, which you could special-case. As config files are generally small files, this is no problem. Of course you should check whether the file you are going to patch is the file you assume it is, but this is easily built-in to binary diff using a hash. If a file doesn't match, err on the safe side and simply fetch the entire package.