When upgrading web applications it can make life much easier to get a list of files that have changed since the last version. This way you only have to overwrite a small number of files so if you won’t have to make all of your customizations again. The best application to use on Windows to do this is WinDiff. WinDiff is a very lightweight application that does not require installation to run. Below are some screenshots of WinDiff, where to download WinDiff, and instructions on how to compare two directories of like files.